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                                                                   Exhibit 10.16

                          SERIES CC PURCHASE AGREEMENT

                  THIS SERIES CC PURCHASE AGREEMENT (this "AGREEMENT"), dated as
of February 14, 2002, is by and between funds and accounts managed by affiliates
of Putnam Investments, LLC, a Delaware limited liability company ("PUTNAM"), the
other parties listed on SCHEDULE A hereto (collectively with Putnam, the
"PURCHASERS") and CommVault Systems, Inc., a Delaware corporation (the
"COMPANY").

                  WHEREAS, each of the Purchasers desire to invest in the
Company; and

                  WHEREAS, the Company desires to issue and sell to the
Purchasers an aggregate of 7,345,896 shares of its Series CC Preferred Stock
(the "SHARES") and the Purchasers desire to purchase the Shares on the terms and
subject to the conditions described herein.

                  NOW, THEREFORE, in consideration of the premises and of the
mutual covenants, agreements and warranties herein contained, the parties hereto
agree as follows:

                  1. DEFINITIONS. Capitalized terms that are not defined in the
text of this Agreement have the meanings set forth below:

         "Affiliate" shall mean, with respect to any specified Person, any other
Person which, directly or indirectly, owns, manages or controls, is under common
ownership, management or control with, or is owned, managed or controlled by,
such specified Person and, with respect to Putnam, any funds or accounts where
Putnam Investment Management, LLC or its affiliates, acts as Investment Adviser
(as defined in the Investment Advisers Act of 1940, as amended). For purposes of
this definition, a Person shall be deemed to control another Person if the first
Person owns, manages or holds more than 50% of the voting power of the second
Person.

         "Amended Certificate" shall mean the Amended and Restated Certificate
of Incorporation of the Company in the form of EXHIBIT 2.

         "Board of Directors" shall mean the board of directors of the Company.

         "Code" means the Internal Revenue Code of 1986 or any successor
statute, and the rules and regulations thereunder, collectively and as from time
to time amended and in effect.

         "Commission" shall mean the Securities and Exchange Commission.

         "Conversion Shares" shall have the meaning set forth in Section 5(e).

         "ERISA" means the Employee Retirement Income Security Act of 1974 or
any successor statute and the rules and regulations thereunder, collectively and
as from time to time amended and in effect.

         "Governmental Authority" shall mean the government of the United States
or any foreign country or any state or political subdivision thereof and any
entity, body or authority exercising executive, legislative, judicial,
regulatory or administrative functions of or pertaining to government.

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         "Initial Public Offering" shall mean the initial public offering or
sale of common stock by the Company through underwriters or otherwise, that
requires registration, qualification or the filing of a prospectus under the
Securities Act.

         "Knowledge" means the actual knowledge (assuming reasonable
investigation) of N. Robert Hammer, Louis Miceli, Larry Cormier, Al Bunte, Lee
Parker and the other senior executives of the Company.

         "Law" shall mean any law, statute, regulation, ordinance, rule, order,
decree, judgment, consent decree, settlement agreement or governmental
requirement enacted, promulgated, entered into, agreed or imposed by any
Governmental Authority.

         "Lien" shall mean any mortgage, lien (except for any lien for taxes not
yet due and payable), charge, restriction, pledge, security interest, option,
lease or sublease, claim, right of any third party, easement, encroachment or
encumbrance.

         "Material Adverse Effect" shall mean an effect on the business,
operations, assets, liabilities, results of operations, cash flows or condition
(financial or otherwise) of the Company which is material and adverse.

         "Non-Preemptive Shares" shall mean any voting shares of the capital
stock of the Company issued, sold, granted or conveyed (i) as consideration in
any acquisition of all or a portion of any Person or a merger or combination
with any Person duly authorized by the Board of Directors, (ii) to any current
or new director, officer, employee or consultant of the Company pursuant to any
plan or arrangement, now or hereafter existing, duly authorized by the Board of
Directors or (iii) pursuant to any of the items listed on SCHEDULE C.

         "Person" shall mean any individual, corporation, proprietorship, firm,
partnership, limited liability company, limited partnership, trust, association,
Massachusetts business trust or other entity.

         "Preferred Stock" shall mean, collectively, the Company's issued and
outstanding Series A Preferred Stock, Series B Preferred Stock, Series C
Preferred Stock, Series D Preferred Stock, Series E Preferred Stock, Series AA
Preferred Stock and Series BB Preferred Stock.

         "Registration Rights Agreement" shall mean a Registration Rights
Agreement to be entered into between Purchasers and the Company as of the
Closing in the form of EXHIBIT 1.

         "Securities Act" shall mean the Securities Act of 1933, as amended.

         "Series AA Purchase Agreement" shall mean the Purchase Agreement, dated
as of April 14, 2000 between the Company and the other Persons party thereto.

         "Series AA Registration Rights Agreement" shall mean the Registration
rights Agreement, dated as of April 14, 2000, between the Company and the
holders of the Company's Series AA Preferred Stock.

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         "Series BB Purchase Agreement" shall mean the Purchase Agreement, dated
as of November 10, 2000, by and between the Company and the other Persons party
thereto.

         "Series BB Registration Rights Agreement" shall mean the Registration
Rights Agreement, dated as of November 10, 2000, between the Company and the
holders of the Series BB Preferred Stock.

         "Stock Plan" shall mean the Company's stock plan, as described on
SCHEDULE C.

         "Stockholders' Agreement" shall mean the stockholders' agreement, dated
as of May 22, 1996, and as further amended, between the Company and certain of
its stockholders.

         "Subsidiaries" shall mean the Persons set forth on SCHEDULE B.

                  2. PURCHASE AND SALE OF SHARES.

         (a) PURCHASE PRICE. Subject to the terms and conditions set forth in
this Agreement, at the Closing (as hereinafter defined), the Purchasers shall
purchase, and the Company shall issue and sell to the Purchasers the Shares for
an aggregate purchase price (the "Purchase Price") of $23,000,000. The number of
Shares being sold to each Purchaser and the portion of the Purchase Price
attributable thereto is set forth on SCHEDULE A hereto.

         (b) CLOSING. The closing (the "Closing") of the transactions described
herein shall occur at 10:00 a.m. on February 14, 2002, at the offices of Ropes &
Gray, One International Place, Boston, Massachusetts, or such other place and
time as agreed upon by the Purchasers and the Company. At the Closing, the
Purchasers shall pay the Company the Purchase Price in cash by wire transfer of
immediately available funds to an account designated by the Company, which
designation shall occur at least two business days before the Closing, and the
Company shall deliver to each Purchaser a certificate representing the Shares
purchased by such Purchaser; provided, that, if so requested by a Purchaser that
is an Affiliate of Putnam, the Company will deliver such certificate to such
Purchaser's custodian at least one business day prior to the Closing pursuant to
an escrow arrangement reasonably acceptable to such custodian, the Company and
Putnam.

                  3. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company
hereby represents and warrants to each of the Purchasers:

         (a) DUE INCORPORATION; SUBSIDIARIES. Each of the Company and the
Subsidiaries is duly incorporated, validly existing and in good standing under
the laws of its jurisdiction of incorporation, with all requisite power and
authority to own, lease and operate its properties and to carry on its business
as they are now being owned, leased, operated and conducted. Each of the Company
and the Subsidiaries is licensed or qualified to do business and is in good
standing as a foreign corporation in each jurisdiction where the nature of the
properties owned, leased or operated by it and the businesses transacted by it
require such licensing or qualification, except where the failure to be so
licensed or qualified would not individually or in the aggregate have a Material
Adverse Effect. Except as set forth on SCHEDULE B, the Company has no direct or
indirect subsidiaries, either wholly or partially owned, and the Company does
not hold any direct

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or indirect economic, voting or management interest in any Person or directly or
indirectly own any security issued by any Person. Each Subsidiary is wholly
owned by the Company.

         (b) DUE AUTHORIZATION. The Company has full power and authority to
enter into this Agreement and the Registration Rights Agreement and to
consummate the transactions contemplated hereby and thereby. The execution,
delivery and performance by the Company of this Agreement and the Registration
Rights Agreement have been duly and validly approved by the board of directors
of the Company and no other actions or proceedings on the part of the Company
are necessary to authorize this Agreement, the Registration Rights Agreement and
the transactions contemplated hereby and thereby. The Company has duly and
validly executed and delivered this Agreement and has duly and validly executed
and delivered the Registration Rights Agreement. This Agreement constitutes
legal, valid and binding obligations of the Company and the Registration Rights
Agreement upon execution and delivery by the Company will constitute legal,
valid and binding obligations of the Company, in each case, enforceable in
accordance with their respective terms, except as such enforceability may be
limited by applicable bankruptcy, insolvency, moratorium, reorganization or
similar laws in effect which affect the enforcement of creditors' rights
generally and by equitable limitations on the availability of specific remedies.

         (c) CONSENTS AND APPROVALS; AUTHORITY RELATIVE TO THIS AGREEMENT.

                  (i) Except for (x) the approval of the Amended Certificate by
the Company's stockholders and the filing of such certificate with the Delaware
Secretary of State, (y) approval of amendments to the Series AA Registration
Rights Agreement, the Series BB Registration Rights Agreement and the
Stockholders' Agreement and (z) waivers by the holders of the Company's
Preferred Stock of preemptive rights to purchase the Shares (the consents,
amendments and waivers described in clauses (x), (y) and (z) being the "REQUIRED
CONSENTS"), no consent, authorization or approval of, filing or registration
with, or cooperation from, any Governmental Authority or any other Person not a
party to this Agreement that has not been received by the Company is necessary
in connection with the execution, delivery and performance by the Company of
this Agreement and the execution, delivery and performance by the Company of the
Registration Rights Agreement or the consummation of the transactions
contemplated hereby or thereby (including, without limitation, the offer,
issuance, sale and delivery of the Shares and the Conversion Shares).

                  (ii) Assuming receipt of the Required Consents, the execution,
delivery and performance by the Company of this Agreement and the Registration
Rights Agreement or the consummation of the transactions contemplated hereby or
thereby do not and will not (1) violate any Law; (2) violate or conflict with,
result in a breach or termination of, constitute a default or give any third
party any additional right (including a termination right) under, permit
cancellation of, result in the creation of any Lien upon any of the assets or
properties of the Company under, or result in or constitute a circumstance
which, with or without notice or lapse of time or both, would constitute any of
the foregoing under, any contract to which the Company, is a party or by which
the Company or any of its assets or properties are bound; (3) permit the
acceleration of the maturity of any indebtedness of the Company or indebtedness
secured by its assets or properties; or (4) violate or conflict with any
provision of any of the Amended Certificate or by-laws of the Company.

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         (d) CAPITALIZATION.

                  (i) The authorized capital stock of the Company is as
described in the Amended Certificate. All of the outstanding capital stock of
the Company and each Subsidiary (i) is validly issued, fully paid and
nonassessable and (ii) is free of preemptive rights (except as provided in the
Stockholders' Agreement, Series AA Purchase Agreement, the Series BB Purchase
Agreement or this Agreement). When issued, the Shares and the Conversion Shares
will be validly issued, fully paid and nonassessable and will not have been
issued in violation of any preemptive rights or rights of first refusal. The
authorized capital stock as described in the Amended Certificate contains a
sufficient number of shares of common stock for issuance of the Conversion
Shares.

                  (ii) Except as set forth above or on SCHEDULE C, there are no
shares of capital stock or other securities (whether or not such securities have
voting rights) of the Company issued or outstanding or any subscriptions,
options, warrants, calls, rights, convertible securities or other agreements or
commitments of any character obligating the Company to issue, transfer or sell,
or cause the issuance, transfer or sale of, any shares of its capital stock or
other securities (whether or not such securities have voting rights). Except as
set forth in SCHEDULE C, there are no outstanding contractual obligations of the
Company which relate to the purchase, sale, issuance, repurchase, redemption,
acquisition, transfer, disposition, holding or voting of any shares of its
capital stock or other securities. The maximum number of shares of common stock
that the Company has issued and would be obligated to issue as of the date
hereof is 63,877,195 shares on a fully diluted basis, plus any Shares issued
hereunder and the shares issuable pursuant to the warrants listed in paragraphs
6 and 7 of SCHEDULE C. The outstanding capital stock of the Company immediately
prior to the Closing and before the issuance of the Shares is as follows: (i)
2,039,717 shares of Series A Preferred Stock, (ii) 346,000 shares of Series B
Preferred Stock, (iii) 333,333 shares of Series C Preferred Stock, (iv) 247,204
shares of Series D Preferred Stock, (v) 200,000 shares of Series E Preferred
Stock, (vi) 4,361,555 shares of Series AA Preferred Stock, (vii) 2,758,358
shares of Series BB Preferred Stock and (viii) 36,072,643 shares of Common
Stock.

         (c) LITIGATION.

                  (i) There is no claim, action, suit, investigation or
proceeding ("LITIGATION") pending or, to the Knowledge of the Company,
threatened against the Company or any Subsidiary, or involving any of its
properties or assets by or before any court, arbitrator or other Governmental
Entity which (1) in any manner challenges or seeks to prevent, enjoin, alter or
materially delay the transactions contemplated by this Agreement or (2) if
resolved adversely to the Company or any Subsidiary, would reasonably be
expected to have a Material Adverse Effect.

                  (ii) Neither the Company nor any Subsidiary is in default
under or in breach of any order, judgment or decree of any court, arbitrator or
other Governmental Authority.

         (f) INTELLECTUAL PROPERTY.

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                  (i) The Company owns all right, title and interest in, or, to
the Knowledge of the Company has the right to use: all patents and the
inventions claimed therein; trademarks, service marks and trade names, together
with associated goodwill; copyrights and copyrightable work; Internet domain
names; registrations and applications relating to any of the foregoing;
know-how, processes, formulae, algorithms, models, methodologies and trade
secrets; computer programs, including any and all software implementations of
algorithms, models and methodologies whether in source code or object code form;
databases and compilations, including any and all data, all documentation,
including user manuals and training materials, related to any of the foregoing;
and the content and information contained on any Company Web site; and other
confidential and proprietary information (collectively, the "PROPRIETARY
ASSETS") used in its business as now conducted and as presently proposed to be
conducted. To the Knowledge of the Company, no person or entity has any
ownership right, title, interest, claim in or lien on any of the Company's
Proprietary Assets. No current or former employee, officer, director or
consultant of the Company has any ownership right, right to use, title,
interest, claim in or lien on any of the Company's Proprietary Assets. The
Company has not granted and, to the Knowledge of the Company, there are not
outstanding, any options, licenses or agreements of any kind relating to any
Proprietary Asset of the Company, nor is the Company bound by or a party to any
option, license or agreement of any kind with respect to any of its Proprietary
Assets. No settlement agreements, consents, judgments, orders, forbearance to
sue or similar obligations limit or restrict the Company's rights in and to any
Proprietary Assets.

                  (ii) To the Knowledge of the Company, the Company has not
violated, misappropriated, diluted or infringed, and would not, by conducting
its business as currently proposed, violate, misappropriate, dilute or infringe,
any intellectual property right in any Proprietary Asset of any other person or
entity. There is no claim, action, suit, investigation or proceeding pending or,
to the Knowledge of the Company, threatened against the Company which would
affect in any way any of its Proprietary Assets by or before any court,
arbitrator or other Governmental Entity. To the Knowledge of the Company, no
third party has violated, misappropriated, diluted or infringed any intellectual
property right in any Proprietary Asset of the Company.

                  (iii) The Company takes all reasonable measures to protect the
confidentiality of their trade secrets including requiring third parties having
access thereto to execute written nondisclosure agreements. Each employee of the
Company hired after January 1, 1998 has signed an Employee Inventions and
Confidentiality Agreement substantially in the form attached hereto as SCHEDULE
D.

                  (iv) All material Proprietary Assets owned or used by the
Company have been duly maintained, are valid and subsisting, in full force and
effect and have not been cancelled, expired or abandoned. The execution,
delivery and performance by the Company of this Agreement or the Registration
Rights Agreement, or the consummation of the transactions contemplated hereby or
thereby will not result in the loss or impairment of the Company's rights to own
or use any of the Proprietary Assets, nor will such consummation require the
consent of any third party in respect of any Proprietary Assets.

                  (v) Except for Microsoft Corporation's SQL product, which
Microsoft Corporation has licensed to the Company (with rights to further
sublicense such software), the

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Company's software products (the "PROPRIETARY SOFTWARE") were either developed
(a) by employees of the Company within the scope of their employment; (b) by
independent contractors as "works-made-for-hire," as that term is defined under
Section 101 of the United States Copyright Act, 17 U.S.C. ss. 101, pursuant to
written agreement; or (c) by third parties who have assigned all of their rights
therein to the Company pursuant to a written agreement. No former or present
employees, officers or directors of the Company, or any other third parties
retain any rights of ownership or use of the Proprietary Software, and no
employees or third parties who have developed or participated in the development
of the Proprietary Software have any claims to any moral rights therein.

                  (g) FINANCIAL STATEMENTS. The Company has furnished to each of
the requesting Purchasers a complete and correct copy of the balance sheet of
the Company at September 30, 2001, and statements of income for the period from
January 1, 2001 through September 30, 2001 (collectively, the "FINANCIAL
STATEMENTS"). The Financial Statements are complete and correct, are in
accordance with the books and records of the Company and present fairly in all
material respects the financial condition and results of operations of the
Company, at the dates and for the periods indicated, and have been prepared in
accordance with generally accepted accounting principles ("GAAP") consistently
applied, except that the unaudited Financial Statements may not be in accordance
with GAAP because of the absence of footnotes normally contained therein and are
subject to normal year-end adjustments which in the aggregate are not expected
to be material.

                  (h) ABSENCE OF UNDISCLOSED LIABILITIES. The Company does not
have any liability (whether known or unknown and whether absolute or
contingent), except for (a) liabilities shown on the face of the Financial
Statements and (b) liabilities that have arisen since September 30, 2001 in the
ordinary course of business that are not material.

                  (i) ABSENCE OF CHANGES. Since September 30, 2001, the Company
has conducted its business in the ordinary course, consistent with past practice
and there has not been any event or condition which has had or would be
reasonably expected to have, individually or in the aggregate, a Material
Adverse Effect.

                  (j) CONTRACTS. The Company does not have and is not bound by
any contract, agreement, lease or commitment, other than (i) contracts for the
purchase of supplies and services or the licensing of technology that were
entered into in the ordinary course of business that do not involve more than
$250,000 per year and do not extend for more than one year, (ii) sales contracts
entered into in the ordinary course of business, (iii) the leases for the
Company's office or other space, (iv) contracts terminable at will by the
Company on no more than 30 days' notice without cost or liability to the
Company, (v) an agreement with Microsoft Corporation, dated as of April 12,
2000, or (vi) other contacts the loss of which would not have a Material Adverse
Effect. Except for (i) an engineering and marketing agreement, dated as of April
12, 2000, between the Company and Microsoft Corporation, (ii) a warrant, dated
as of April 14, 2000, granting Microsoft Corporation the right to purchase
common stock of the Company under certain conditions and (iii) an agreement with
Microsoft Corporation, pursuant to which the Company licenses and has the
further right to sublicense Microsoft's SQL product, the Company has provided
the Purchasers with a copy of all its material contracts. To the

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Knowledge of the Company, all of the contracts to which it is a party are valid
and binding and are in full force and effect as of the date of this Agreement.

                  (k) REGISTRATION RIGHTS. Other than the Registration Rights
Agreement, the Series AA Registration Rights Agreement, the Series BB
Registration Rights Agreement, the Stockholders Agreement and the piggyback
registration rights granted pursuant to the Purchase Agreement listed in
paragraph 4 of SCHEDULE C, the Company has not granted any registration rights
to any party for any of its securities.

                  (l) COMPLIANCE WITH LAWS. The Company and each Subsidiary are
in compliance in all material respects with all applicable Laws. All securities
issued by the Company prior to the date hereof have been issued in transactions
exempt from the registration requirements of Section 5 of the Securities Act.

                  (m) OFFERING OF SHARES. Neither the Company nor any Person
acting on its behalf has taken or will take any action (including, without
limitation, any offering of any securities of the Company under circumstances
which would require, under the Securities Act, the integration of such offering
with the offering and sale of the Shares) which might reasonably be expected to
subject the offering, issuance or sale of the Shares to the registration
requirements of the Securities Act. Subject to the continuing accuracy of the
Purchasers' representations in Section 4, the offer, sale and issuance of the
Shares and the Conversion Shares in conformity with the terms of this Agreement
and the Amended Certificate constitute or will constitute transactions exempt
from the registration requirements of Section 5 of the Securities Act.

                  (n) BROKERS. Except for fees and commissions payable to Credit
Suisse First Boston Corporation by the Company, no broker, finder or investment
banker is entitled to any brokerage, finder's or other fee or commission from
any party in connection with the transactions contemplated by this Agreement
based upon arrangements made by or on behalf of the Company.

                  (o) INSURANCE COVERAGE. The Company maintains in full force
and effect insurance coverage that the Company reasonably believes to be
adequate against all liabilities, claims and risks against which it is customary
for comparably situated companies to insure.

                  (p) EMPLOYEES. To the Company's Knowledge, no executive, key
employee, or group of employees has any plans to terminate employment with the
Company. The Company is in compliance in all material respects with all
applicable laws respecting employment and employment practices and terms and
conditions of employment.

                  (q) ERISA. The Company does not have or otherwise contribute
to or participate in any employee benefit plan subject to Title IV of ERISA.

                  (r) ENVIRONMENTAL MATTERS. The Company is not in violation of
any statute, rule, regulation, decision or order of any governmental agency or
body or any court, domestic or foreign, relating to the use, disposal or release
of hazardous or toxic substances or relating to the protection or restoration of
the environment or human exposure to hazardous or toxic substances
(collectively, "ENVIRONMENTAL LAWS"), does not own or operate any real property
contaminated with any substance that is subject to any Environmental Laws, is
not liable for any off-site

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disposal or contamination pursuant to any Environmental Laws, and is not subject
to any claim relating to any Environmental Laws, which violation, contamination,
liability or claim would individually or in the aggregate have a Material
Adverse Effect; and the Company is not aware of any pending investigation that
might lead to such a claim.

                  (s) AFFILIATED TRANSACTIONS. Other than the Stockholders'
Agreement and the side letters with holders of the Company's Series A through E
Preferred Stock dated the date hereof, the Company is not, nor has it been, a
party to or bound by any contract, agreement, lease or commitment with any of
the Affiliates of the Company, other than on arms-length terms which are no less
favorable to the Company than those which could be obtained with a third party
which is not an Affiliate of the Company and no Affiliate of the Company owns or
otherwise has any rights to or interests in any asset, tangible or intangible,
which is used in the conduct of the Company's business.

                  (t) NO ILLEGAL PAYMENTS. In connection with the conduct of the
Company's business, none of the Company nor any of their directors or officers
nor, to the Company's Knowledge, any of their employees or agents, has (x)
directly or indirectly given or agreed to give any illegal gift, contribution,
payment or similar benefit to any supplier, customer, governmental official or
employee or other person who was, is or may be in a position to help or hinder
the Company (or assist in connection with any actual or proposed transaction) or
made or agreed to make any illegal contribution, or reimbursed any illegal
political gift or contribution made by any other person, to any candidate for
federal, state, local or foreign public office (i) which might subject the
Company to any damage or penalty in any civil, criminal or governmental
litigation or proceeding or (ii) the non-continuation of which has had or might
have a Material Adverse Effect or (y) established or maintained any unrecorded
fund or asset or made any false entries on any books or records for any purpose.

                  (u) DISCLOSURE. The representations and warranties contained
in this Section 3 (including any schedules and exhibits required to be delivered
by the Company to the Purchasers pursuant to this Agreement) and any certificate
furnished or to be furnished by the Company to the Purchasers do not contain and
on the date of the Closing will not contain any untrue statement of a material
fact or omit to state any material fact necessary in order to make the
statements and information contained in this Section 3 not misleading.

                  4. REPRESENTATIONS AND WARRANTIES OF PURCHASERS. Each of the
Purchasers severally but not jointly hereby represents and warrants to the
Company as follows:

         (a) DUE INCORPORATION. Each Purchaser that is not an individual is duly
organized or duly formed, validly existing and in good standing under the laws
of its jurisdiction of organization, with all requisite power and authority to
own, lease and operate its properties and to carry on its business as they are
now being owned, leased, operated and conducted.

         (b) DUE AUTHORIZATION. Each Purchaser that is not an individual has
full power and authority to enter into this Agreement and the Registration
Rights Agreement and to consummate the transactions contemplated hereby and
thereby. The execution, delivery and performance by such Purchaser of this
Agreement and the Registration Rights Agreement have been duly and validly
approved by its governing body empowered to authorize the transactions
contemplated

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by this Agreement and the Registration Rights Agreement and no other actions or
proceedings on the part of such Purchaser are necessary to authorize this
Agreement, the Registration Rights Agreement and the transactions contemplated
hereby and thereby.

         (c) DUE EXECUTION; BINDING EFFECT. Such Purchaser has validly executed
and delivered this Agreement and has duly and validly executed and delivered (or
prior to or at the Closing will duly and validly execute and deliver) the
Registration Rights Agreement. This Agreement constitutes legal, valid and
binding obligations of such Purchaser and such Purchaser's Related Agreements
upon execution and delivery by such Purchaser (as applicable) will constitute
legal, valid and binding obligations of such Purchaser, in each case,
enforceable in accordance with their respective terms, except as such
enforceability may be limited by applicable bankruptcy, insolvency, moratorium,
reorganization or similar laws in effect which affect the enforcement of
creditors' rights generally and by equitable limitations on the availability of
specific remedies.

         (d) CONSENTS AND APPROVALS; AUTHORITY RELATIVE TO THIS AGREEMENT.

                  (i) No consent, authorization or approval of, filing or
registration with, or cooperation from, any Governmental Authority or any other
Person not a party to this Agreement is necessary in connection with the
execution, delivery and performance by such Purchaser of this Agreement and the
Registration Rights Agreement and the consummation by such Purchaser of the
transactions contemplated hereby and thereby.

                  (ii) The execution, delivery and performance by such Purchaser
of this Agreement and the Registration Rights Agreement do not and will not (1)
violate any Law applicable to such Purchaser; (2) violate or conflict with,
result in a breach or termination of, constitute a default or give any third
party any additional right (including a termination right) under, permit
cancellation of, result in the creation of any Lien upon any of the assets or
properties of such Purchaser under, or result in or constitute a circumstance
which, with or without notice or lapse of time or both, would constitute any of
the foregoing under, any contract to which Purchaser is a party or by which such
Purchaser or any of its assets or properties are bound; (3) permit the
acceleration of the maturity of any indebtedness of such Purchaser or
indebtedness secured by its assets or properties; or (4) for each Purchaser that
is not an individual, violate or conflict with any provision of such Purchaser's
organizational documents.

         (e) BROKERS. No broker, lender or investment banker is entitled to any
brokerage, lender's or other fee or commission from any party in connection with
the transactions contemplated by this Agreement based on arrangements made by or
on behalf of such Purchaser.

         (f) PURCHASE FOR INVESTMENT. Such Purchaser is purchasing the Shares
hereunder for investment without any intent of the distribution thereof within
the meaning of the Securities Act.

         (g) ACCREDITED INVESTOR. Such Purchaser is an "accredited investor"
within the meaning of Regulation 501(a) under the Securities Act and is able to
bear the economic risk of acquisition of the Shares, can afford to sustain a
total loss on such investment, and has such knowledge and experience in
financial and business matters that it is capable of evaluating the

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merits and risk of the proposed investment. Such Purchaser has been furnished
the opportunity to ask questions of and receive answers from representatives of
the Company concerning the business and financial affairs of the Company.

                  5. COVENANTS.

         (a) FINANCIAL INFORMATION. 1. As soon as practicable after the end of
each fiscal year of the Company, and in any event within 120 days thereafter,
upon the request of such Purchaser, the Company shall furnish to each Purchaser
that holds (together with its Affiliates) at least 500,000 Shares, an audited
balance sheet and income statement of the Company (the "FINANCIAL INFORMATION")
as at the end of such fiscal year, prepared in accordance with GAAP consistently
applied.

                  (2) As soon as practicable after the end of the first, second
and third quarterly accounting periods in each fiscal year of the Company, and
in any event within 60 days thereafter, upon the request of such Purchaser, the
Company shall furnish to each Purchaser that holds (together with its
Affiliates) at least 500,000 Shares, unaudited Financial Information for such
period and for such fiscal year to date, prepared in accordance with GAAP
consistently applied, subject to changes resulting from normal year-end audit
adjustments, and except that such Financial Information need not contain the
notes required by GAAP.

                  (3) Each Purchaser acknowledges that any information obtained
by such Purchaser pursuant to this Section 5(a) that may be proprietary to the
Company or otherwise confidential shall not be disclosed (other than as required
by law or by Section 5(b)) without the prior written consent of the Company.
Each Purchaser further acknowledges and understands that any information so
obtained that may be considered "inside" non-public information shall not be
utilized by such Purchaser in connection with purchases and/or sales of the
Company's securities except in compliance with applicable state and federal
antifraud statutes. The Company may exclude a Purchaser from the distribution of
the information to be delivered pursuant hereto if the Board of Directors
determines in good faith upon advice of counsel that such exclusion is
reasonably necessary to preserve attorney-client privilege or to protect other
similar confidential information. The rights and obligations of the parties
pursuant to this Section 5(a) shall terminate upon the closing of an Initial
Public Offering.

         (b) BOARD OBSERVER. So long as Putnam holds at least 2,000,000 Shares,
Putnam shall be entitled to designate one non-voting observer (the "NON-VOTING
OBSERVER") to attend (but not vote at) all meetings of the Board of Directors
and all committees thereof. The Non-Voting Observer shall have the same access
to information concerning the business and operations of the Company and at the
same time as the directors of the Company, except for such information that the
Company reasonably determines it cannot distribute for confidentiality reasons,
and shall be entitled to ask questions of the Board of Directors, but shall not
be entitled to vote. Putnam's right to nominate the Non-Voting Observer and all
rights of the Putnam Non-Voting Observer shall terminate upon the earlier of (a)
written notice of termination by Putnam to the Company or (b) the date the
Company requests the Commission to accelerate the effectiveness of the Company's
registration statement relating to the Initial Public Offering. The rights of
any other Purchasers, including the rights to have access to the books and
records of the Company and other information as provided above, shall terminate
as of the date of the Company's final

                                      -11-

<PAGE>

prospectus relating to the Initial Public Offering. Subject to any other
agreement between the parties, Putnam and any other Purchaser that receives
information agrees that the information provided by the Company, officers,
directors and employees pursuant to Section 5(a) and Section 5(b) will be used
solely for the purpose of evaluating such Purchaser's investment in the Shares
and the Conversion Shares, as applicable, and that such information will be kept
strictly confidential by such Purchaser; PROVIDED that the foregoing obligation
of such Purchaser shall not (a) relate to any information that (i) is or becomes
generally available other than as a result of unauthorized disclosure by such
Purchaser or by persons to whom such Purchaser has made such information
available, (ii) is already in such Purchaser's possession, provided that such
information is not subject to another confidentiality agreement with or other
obligation of secrecy to the Company or (iii) is or becomes available to such
Purchaser on a non-confidential basis from a third party that is not, to such
Purchaser's knowledge, bound by any other confidentiality agreement with the
Company or its subsidiaries, or (b) prohibit disclosure of any information if
required by Law or the rules of any stock exchange. Putnam and each other
Purchaser hereby acknowledges that it is aware that the United States securities
laws prohibit any person who has received from an issuer or any Affiliate
thereof any material, non-public information from purchasing or selling
securities of such issuer or from communicating such information to any other
person under circumstances in which it is reasonably foreseeable that such
person is likely to purchase or sell such securities.

         (c) AMENDED CERTIFICATE. The Company shall, prior to the Closing, cause
the Amended Certificate to be filed with the Secretary of State of the State of
Delaware.

         (d) COOPERATION. Each of the Purchasers and the Company agrees to use
its reasonable best efforts to take, or cause to be taken, all such further
actions as shall be necessary to make effective and consummate the transactions
contemplated by this Agreement.

         (e) RESERVE SHARES. The Company will at all times reserve and keep
available, solely for issuance and delivery upon conversion of the Shares, the
number of shares of common stock from time to time issuable upon conversion of
all Shares at the time outstanding (the "CONVERSION SHARES"). All Conversion
Shares shall be duly authorized and, when issued upon such conversion in
accordance with the Amended Certificate, shall be validly issued, fully paid and
nonassessable.

         (f) RESTRICTIONS ON TRANSFER. The Purchasers will not, prior to the
earlier of (a) December 31, 2004 or (b) the time of the closing of the Initial
Public Offering, sell, transfer, assign, convey, gift, mortgage, pledge,
encumber, hypothecate, or otherwise dispose of, directly or indirectly,
("TRANSFER") any of the Shares or any Conversion Shares except for (i) Transfers
between and among the Purchasers and their Affiliates provided such Transfer is
in accordance with the transfer restrictions applicable to the Shares or the
Conversion Shares under federal and state securities laws and the Affiliate
transferee agrees to be bound by the restrictions applicable to such Shares or
Conversion Shares, including without limitation the agreements set forth in this
Section 5(f), and (ii) Transfers (x) pursuant to a bona fide tender or exchange
offer made pursuant to a merger or other agreement approved by the Board of
Directors to acquire securities of the Company, (y) pursuant to any cash merger,
or other business combination transaction to which the Company is a party or
involved in which the common stock of the Company's stockholders is exchanged
for cash upon consummation of such merger or other business

                                      -12-

<PAGE>

combination or (z) agreed to in writing by the Company. Notwithstanding any
other provision of this Section 5(f), no Purchaser shall avoid the provisions of
this Section 5(f) by making one or more transfers to one or more Affiliates and
then disposing of all or any portion of such Purchaser's interest in any such
Affiliate.

         (g) PREEMPTIVE RIGHT. If at any time the Company desires to issue or
sell any shares of its capital stock or securities convertible, exercisable or
exchangeable for the Company's capital stock (other than Non-Preemptive Shares)
(the "ADDITIONAL SHARES") to any Person, the Company shall give a written notice
(the "ISSUANCE NOTICE") to the Purchasers setting forth the proposed terms of
the sale of such Additional Shares and the quantity of Additional Shares to be
issued, the proposed issuance date and the price at which such Additional Shares
shall be issued. Each of the Purchasers shall have the option to purchase the
number of Additional Shares necessary to maintain such Purchaser's percentage of
issued and outstanding shares of the Company at the time of the Issuance Notice,
which option may be exercised by giving written notice to the Company (the
"RESPONSE NOTICE") within 14 days of the Issuance Notice that contains an
agreement to purchase all or any portion of the Additional Shares to which such
Purchaser is entitled to purchase. Failure by a Purchaser to give the Response
Notice to the Company within such 14-day period shall be deemed to be a
rejection of such option. For a period of 180 days after any Issuance Notice,
the Company shall have the right to issue or sell to any Person (a "THIRD PARTY
BUYER") up to the number of Additional Shares specified in the Issuance Notice
less the number of Additional Shares subscribed for pursuant to duly tendered
Response Notices at the same price and on other terms not materially less
favorable to the Company than as specified in the Issuance Notice. At the time
of the closing of the sale of the Additional Shares to one or more Third Party
Buyers, the Company shall sell to such Purchaser and such Purchaser shall
purchase the Additional Shares that such Purchaser agreed to purchase in the
Response Notice, at the price and on the terms set forth in the Issuance Notice.
If at the end of the 180th day following any Issuance Notice, the Company has
not completed the issuance described in the Issuance Notice, each Purchaser that
has provided a Response Notice shall be released from its obligations
thereunder. If the Company desires to issue or sell Additional Shares, (i) after
such 180-day period, (ii) except in connection with an Initial Public Offering,
on terms materially less favorable to the Company than as specified in the
Issuance Notice, (iii) except in connection with an Initial Public Offering, at
a price less than the price specified in the Issuance Notice or (iv) except in
connection with an Initial Public Offering, in a quantity greater than as
specified in the Issuance Notice, the Company must again comply with this
Section 5(g). If the Company desires to take any of the actions set forth in
clauses (ii), (iii) or (iv) of the prior sentence in connection with an Initial
Public Offering, each Purchaser, at its option, shall be released from its
obligations under its Response Notice. The rights and obligations of the parties
pursuant to this Section 5(g) shall terminate upon the closing of an Initial
Public Offering.

         (h) COMPLIANCE WITH SECURITIES LAWS. Such Purchaser understands that
the Shares and the Conversion Shares will not be registered under the Securities
Act or applicable state securities laws and agrees not to sell, pledge or
otherwise transfer any of the Shares and Conversion Shares in the absence of
such registration or an opinion of counsel reasonably satisfactory to the
Company that such registration is not required, except that the requirement of a
legal opinion will not apply to transfers by Putnam to any of its Affiliates.
Except as set forth

                                      -13-

<PAGE>

in the Registration Rights Agreement, such Purchaser acknowledges that the
Company is not required to register the Shares or the Conversion Shares.

                  6. CONDITIONS.

         (a) CONDITIONS TO OBLIGATIONS OF THE PURCHASERS. The obligations of the
Purchasers to consummate the transactions contemplated hereby shall be subject
to the satisfaction or waiver at or prior to the Closing of each of the
following conditions:

                  (i) No statute, rule or regulation or order of any court or
administrative agency shall be in effect which prohibits the consummation of the
transactions contemplated hereby;

                  (ii) The Company shall have performed, satisfied and complied
in all material respects with all of its covenants and agreements set forth in
this Agreement to be performed, satisfied and complied with prior to or at the
Closing;

                  (iii) The representations and warranties of the Company in
Section 3 shall be true and correct in all material respects as of the date of
Closing;

                  (iv) The Company shall have executed and delivered to each of
the Purchasers the Registration Rights Agreement;

                  (v) The Company shall have obtained sufficient waivers of
pre-emptive rights from all holders of capital stock who possess such rights so
as to allow the consummation of the transactions contemplated by this Agreement.

                  (vi) The Amended Certificate shall have been duly filed with
the Secretary of State of the State of Delaware in accordance with the laws of
the State of Delaware and the Amended Certificate shall be in full force and
effect;

                  (vii) Mayer, Brown, Rowe & Maw shall have delivered an opinion
in form and substance reasonably satisfactory to Purchasers;

                  (viii) The Company shall have delivered a good standing
certificate for the Company (or a copy thereof) to each of the Purchasers;

                  (ix) The Company shall have received all consents,
authorizations, and approvals necessary to complete the transactions
contemplated hereby, including, without limitation, the Required Consents.

                  (x) The Company shall have delivered to each Purchaser a
certificate of the Company, dated the date of the Closing and executed by the
Chief Executive Officer of the Company, certifying as to the fulfillment of the
conditions specified in Sections 6(a)(ii), (iii), (vi), (xii) and (xiii) of this
Agreement;

                  (xi) The Company shall have delivered to each Purchaser a
certificate of the Company, dated the date of the Closing and executed by the
Secretary of the Company,

                                      -14-

<PAGE>

certifying: (a) the corporate proceedings taken by the Company's Board of
Directors and, if required, stockholders approving this Agreement and the
Registration Rights Agreement and the transactions contemplated hereby and
thereby; (b) the Amended Certificate; and (c) the By-laws of the Company;

                  (xii) No claim, action, cause of action, suit, litigation,
arbitration, investigation, hearing, charge, complaint, demand, notice or
proceeding to, from, by or before any Governmental Authority shall be pending or
threatened wherein an unfavorable injunction, judgment, order, decree, ruling,
or charge would (i) prevent consummation of any of the transactions contemplated
by the Agreement or (ii) cause any of the transactions contemplated by the
Agreement to be rescinded following consummation (and no such injunction,
judgment, order, decree, ruling, or charge shall be in effect); and

                  (xiii) There shall not have occurred any event, circumstances,
condition, fact, effect, or other matter which has had or would reasonably be
expected to have a Material Adverse Effect.

         (b) CONDITIONS TO OBLIGATIONS OF THE COMPANY.  The obligations of the
Company to consummate the transactions contemplated hereby shall be subject to
the satisfaction or waiver at or prior to the Closing of each of the following
conditions:

                  (i) No statute, rule or regulation or order of any court or
administrative agency shall be in effect which prohibits the consummation of the
transactions contemplated hereby;

                  (ii) Each of the Purchasers shall have executed and delivered
to the Company the Registration Rights Agreement;

                  (iii) The representations and warranties of the Purchasers in
Section 4 shall be true and correct in all material respects as of the date of
Closing;

                  (iv) The Company shall have received the Required Consents;
and

                  (v) The Purchasers shall have performed, satisfied and
complied in all material respects with all of their covenants and agreements set
forth in this Agreement to be performed, satisfied and complied with prior to or
at the Closing Date.

                  7. SURVIVAL OF REPRESENTATIONS AND WARRANTIES.

         The representations and warranties of the parties contained in this
Agreement shall expire on the 18-month anniversary of the Closing, except for
those representations and warranties contained in Sections 3(a) through 3(d)
which shall expire on the later of (i) the 18-month anniversary of the Closing
or (ii) the closing of an Initial Public Offering. After the expiration of such
period, any claim by a party based upon any such representation or warranty
shall be of no further force and effect, except to the extent a party has given
notice to the other party of a claim for breach of any such representation or
warranty prior to the expiration of such period, in which event any
representation or warranty to which such claim relates shall survive with
respect to such claim until such claim is resolved. The covenants and agreements
of the parties hereto

                                      -15-

<PAGE>

contained in this Agreement shall survive the Closing until performed in
accordance with their terms.

                  8. RESTRICTIVE LEGENDS. Each certificate representing any
Shares or Conversion Shares shall bear legends in substantially the following
form:

         THE SECURITIES EVIDENCED BY THIS CERTIFICATE SHALL BE CONVERTIBLE INTO
         THE COMPANY'S COMMON STOCK IN THE MANNER AND ACCORDING TO THE TERMS SET
         FORTH IN THE CERTIFICATE OF INCORPORATION. THE COMPANY IS AUTHORIZED TO
         ISSUE MORE THAN ONE CLASS OR SERIES OF STOCK. AS REQUIRED UNDER
         DELAWARE LAW, THE COMPANY SHALL FURNISH TO ANY HOLDER UPON REQUEST AND
         WITHOUT CHARGE, A FULL SUMMARY STATEMENT OF THE DESIGNATIONS, VOTING
         RIGHTS, PREFERENCES, LIMITATIONS AND SPECIAL RIGHTS OF THE SHARES OF
         EACH CLASS OR SERIES AUTHORIZED TO BE ISSUED BY THE COMPANY SO FAR AS
         THEY HAVE BEEN FIXED AND DETERMINED AND THE AUTHORITY OF THE BOARD OF
         DIRECTORS TO FIX AND DETERMINE THE DESIGNATIONS, VOTING RIGHTS,
         PREFERENCES, LIMITATIONS AND SPECIAL RIGHTS OF THE CLASSES AND SERIES
         OF SECURITIES OF THE COMPANY.

         THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "1933 ACT"), OR UNDER
         ANY APPLICABLE STATE LAWS. THE SHARES REPRESENTED BY THIS CERTIFICATE
         HAVE BEEN ACQUIRED BY THE REGISTERED OWNER HEREOF FOR INVESTMENT AND
         NOT WITH A VIEW TO OR FOR SALE IN CONNECTION WITH ANY DISTRIBUTION
         THEREOF WITHIN THE MEANING OF THE 1933 ACT. THE SHARES MAY NOT BE SOLD,
         PLEDGED, TRANSFERRED OR ASSIGNED EXCEPT IN A TRANSACTION WHICH IS
         EXEMPT UNDER THE PROVISIONS OF THE 1933 ACT OR ANY APPLICABLE STATE
         SECURITIES LAWS, OR PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT OR
         IN A TRANSACTION OTHERWISE IN COMPLIANCE WITH APPLICABLE FEDERAL AND
         STATE SECURITIES LAWS.

         THE SALE, PLEDGE, TRANSFER, ASSIGNMENT OR OTHER DISPOSITION OF THE
         SHARES REPRESENTED BY THIS CERTIFICATE IS RESTRICTED BY AND SUBJECT TO
         THE PROVISIONS OF A PURCHASE AGREEMENT DATED AS OF FEBRUARY 14, 2002, A
         COPY OF WHICH IS AVAILABLE UPON REQUEST FOR INSPECTION AT THE OFFICE'S
         OF THE COMPANY. ANY SUCH REQUEST SHOULD BE ADDRESSED TO THE SECRETARY
         OF THE COMPANY.

                  9. SUCCESSORS AND ASSIGNS; NO THIRD PARTY BENEFICIARIES. This
Agreement shall bind and inure to the benefit of the Company and the Purchasers
and the respective successors, permitted assigns, heirs and personal
representatives of the Company and the Purchasers;

                                      -16-

<PAGE>

PROVIDED that the Company may not assign its rights or obligations under this
Agreement to any Person without the prior written consent of the Purchasers, and
PROVIDED FURTHER that the Purchasers may not assign their rights or obligations
under this Agreement to any Person (other than an Affiliate) without the prior
written consent of the Company. This Agreement is intended for the benefit of
the parties hereto and their respective permitted successors and assigns, and is
not for the benefit of, nor may any provision hereof be enforced by, any other
person.

                  10. NOTICES. Each notice, demand, request, request for
approval, consent, approval, disapproval, designation or other communication
(each of the foregoing being referred to herein as a notice) required or desired
to be given or made under this Agreement shall be in writing (except as
otherwise provided in this Agreement), and shall be effective and deemed to have
been received (i) when delivered in person, (ii) when sent by fax with receipt
acknowledged, (iii) five days after having been mailed by certified or
registered United States mail, postage prepaid, return receipt requested, or
(iv) the next business day after having been sent by a nationally recognized
overnight mail or courier service, receipt requested. Notices shall be addressed
as set forth below:

         If to Putnam:

                  Putnam Investment Management, LLC
                  Two Liberty Square
                  Boston, MA  02109
                  Attn:  John Verani
                  Facsimile:  (617) 292-1625

         with a copy to:

                  Ropes & Gray
                  One International Place
                  Boston, MA  02110
                  Attn:  Robert L. Nutt, Esq.
                  Facsimile:  (617) 951-7050

         If to any of the other Purchasers, at the address set forth under his
         name on SCHEDULE A.

         If to the Company:

                  CommVault Systems, Inc.
                  2 Crescent Place
                  Oceanport, New Jersey 07757
                  Attn:  N. Robert Hammer
                  Facsimile:  (732) 870-4514

         With a copy to:

                  Mayer, Brown, Rowe & Maw
                  190 S. LaSalle Street
                  Chicago, Illinois 60603

                                      -17-

<PAGE>

                  Attention: Philip J. Niehoff
                  Facsimile: (312) 701-7711

                  11. FURTHER ASSURANCES. At any time or from time to time after
the Closing, the Company, on the one hand, and the Purchasers, on the other
hand, agree to cooperate with each other, and at the request of the other party,
to execute and deliver any further instruments or documents and to take all such
further action as the other party may reasonably request in order to evidence or
effectuate the consummation of the transactions contemplated hereby and to
otherwise carry out the intent of the parties hereunder.

                  12. PUBLIC DISCLOSURE. Except as required by Law or the rules
of any stock exchange (in which case the Company shall give Putnam notice at
least 24 hours prior to any public announcement containing its name), no public
announcement or other publicity regarding the transactions referred to herein
shall be made by any of the Purchasers or the Company or any of their respective
Affiliates, officers, directors, employees, representatives or agents, without
the prior written agreement of the Purchasers and Company, in any case, as to
form, content, timing and manner of distribution or publication; PROVIDED,
HOWEVER, that nothing in this Section shall prevent such parties from (i)
discussing such transactions with those Persons whose approval, agreement or
opinion, as the case may be, is required for consummation or subsequent review
of such particular transaction or transactions or (ii) disclosing such
information about such transactions in a registration statement or prospectus in
connection with the Initial Public Offering or (iii) if the disclosing party is
a Purchaser, disclosing such Purchaser's investment herein provided that such
disclosure does not mention any other Purchaser by name and is approved by the
Company in writing. Each of the parties acknowledge and agree that there would
be no adequate remedy at Law if it fails to perform its obligations under this
Section 12 and accordingly agrees that each of the other parties, in addition to
any other remedy to which it may be entitled at Law or in equity, shall be
entitled to compel specific performance of the obligations of the first party
under this Section 12.

                  13. WAIVER AND AMENDMENT. With the written consent of the
Company and the record holders of 66 2/3% of the Conversion Shares, (i) the
obligations of the Company under this Agreement and the rights of the holders of
the Conversion Shares under this Agreement may be waived (either generally or in
a particular instance, either retroactively or prospectively, and either for a
specified period of time or indefinitely) or (ii) this Agreement may be amended,
changed, discharged or terminated. Notwithstanding the foregoing, (i) if any
waiver of any right or rights granted to a Purchaser under this Agreement would
uniquely affect such Purchaser, then such waiver may be approved or granted by
such Purchaser without the consent or approval of any other Purchaser and (ii)
if any waiver or amendment of any right or rights granted to a Purchaser under
this Agreement would adversely affect only a given Purchaser, then such
amendment or waiver may not be effected without the consent or approval of such
affected Purchaser. Neither this Agreement nor any provisions hereof may be
amended, changed, waived, discharged or terminated orally, but only by a signed
statement in writing.

                  14. ENTIRE AGREEMENT. This Agreement and the Registration
Rights Agreement constitute the entire agreement, and supersede all other prior
agreements and understandings, both written and oral, among the parties hereto
and their affiliates with respect to the matters set forth herein.

                                      -18-

<PAGE>

                  15. SEVERABILITY. If any provision of this Agreement shall be
held invalid, illegal or unenforceable, the validity, legality or enforceability
of the other provisions hereof shall not be affected thereby, and there shall be
deemed substituted for the provision at issue a valid, legal and enforceable
provision as similar as possible to the provision at issue.

                  16. CAPTIONS. The Section references herein are for
convenience of reference only, do not constitute part of this Agreement and
shall not be deemed to limit or otherwise affect any of the provisions hereof.

                  17. COUNTERPARTS. This Agreement may be executed in one or
more counterparts, each of which shall be deemed an original but all of which
shall constitute one and the same instrument.

                  18. GOVERNING LAW. This Agreement shall be governed by, and
construed and enforced in accordance with, the laws of the State of Delaware.

                  19. WAIVER OF JURY TRIAL. THE COMPANY AND THE PURCHASERS
HEREBY WAIVE ANY RIGHT THEY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY
ACTION, PROCEEDING OR LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF, UNDER OR
IN CONNECTION WITH THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                  20. FEES AND EXPENSES. All legal fees and expenses incurred by
Ropes & Gray on behalf of Putnam in connection with the negotiation and drafting
of this Agreement and the transactions contemplated thereby shall be paid by the
Company, up to a total of $40,000. All other costs shall be borne by the party
incurring such cost or expense.

                  21. JOINT PARTICIPATION IN DRAFTING. Each party to this
Agreement has participated in the negotiation and drafting of this Agreement. As
such, the language used herein shall be deemed to be the language chosen by the
parties hereto to express their mutual intent, and no rule of strict
construction will be applied against any party to this Agreement.

                  22. MASSACHUSETTS BUSINESS TRUSTS. A copy of the Agreement and
Declaration of Trust of each Putnam fund or series investment company (each a
"FUND") that is a Massachusetts business trust is on file with the Secretary of
State of the Commonwealth of Massachusetts and notice is hereby given that this
Agreement is executed on behalf of the Trustees of the relevant Fund as Trustees
and not individually and that the obligations of this Agreement are not binding
upon any of the Trustees, officers or shareholders of the Fund individually but
are binding only upon the assets and property of such Fund.

                                     * * * *

                                      -19-

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed and delivered as of the day and year first written above.

                            COMMVAULT SYSTEMS, INC.

                            By: /S/ N. ROBERT HAMMER
                                ------------------------------------------------
                            Name: N. ROBERT HAMMER
                                  ----------------------------------------------
                            Title: PRESIDENT & CHIEF EXECUTIVE OFFICER
                                   ---------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                            PUTNAM OTC AND EMERGING GROWTH FUND
                            PUTNAM FUNDS TRUST-PUTNAM TECHNOLOGY FUND
                            By Putnam Investment Management, LLC

                            By: /S/ JOHN R. VERANI
                                ------------------------------------------------
                            Name: JOHN R. VERANI
                                  ----------------------------------------------
                            Title: SENIOR VICE PRESIDENT
                                   ---------------------------------------------

                            TH LEE, PUTNAM INVESTMENT TRUST -
                            TH LEE, PUTNAM EMERGING OPPORTUNITIES PORTFOLIO
                            By TH Lee, Putnam Capital Management, LLC

                            By: /S/ JOHN R. VERANI
                                ------------------------------------------------
                            Name: JOHN R. VERANI
                                  ----------------------------------------------
                            Title: SENIOR VICE PRESIDENT
                                   ---------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                            EMC INVESTMENT CORPORATION

                            By:/S/ ILLEGIBLE
                                ------------------------------------------------
                            Name:
                                ------------------------------------------------
                            Title:
                                 -----------------------------------------------
                            35 Parkwood Drive
                            Hopkinton, MA  01748
                            Attn: Office of the General Counsel
                            Fax: (508) 497-6915

                                                              PURCHASE AGREEMENT
<PAGE>

                            VAN WAGONER CROSSOVER FUNDS, L.P.

                            By:/S/ WILLIAM X. MINOR
                               -------------------------------------------------
                            Name: WILLIAM X. MINOR
                                  ----------------------------------------------
                            Title: VAN WAGONER CAPITAL MANAGEMENT LLC GENERAL
                                   PARTNER
                                   ---------------------------------------------
                            345 California Street
                            Suite 2450
                            San Francisco, CA 94104
                            Facsimile: (415) 835-5050

                            VAN WAGONER PRIVATE OPPORTUNITIES FUND, L.P.

                            By:/S/ WILLIAM X. MINOR
                               -------------------------------------------------
                            Name: WILLIAM X. MINOR
                                  ----------------------------------------------
                            Title: VAN WAGONER CAPITAL MANAGEMENT LLC GENERAL
                                   PARTNER
                                   ---------------------------------------------
                            345 California Street
                            Suite 2450
                            San Francisco, CA 94104
                            Facsimile: (415) 835-5050

                                                              PURCHASE AGREEMENT
<PAGE>

                            DRW VENTURE PARTNERS LP

                            By:  RBC Dain Rauscher Corporation, its
                            General Partner

                            By:/S/ MARY ZIMMER
                               -------------------------------------------------
                            Name: MARY ZIMMER
                                  ----------------------------------------------
                            Title: DIRECTOR OF FINANCE AND ADMINISTRATION,
                                   RBC CMS
                                   ---------------------------------------------
                            60 South 6th Street
                            Minneapolis, MN 55402
                            Attn: Mary Zimmer MS 54N2
                            Facsimile: (612) 373-1610

                                                              PURCHASE AGREEMENT
<PAGE>

                            WHEATLEY PARTNERS III, L.P.

                            By:  Wheatley Partners III LLC, its
                            General Partner

                            By:/S/ IRWIN LIEBER
                               -------------------------------------------------
                            Name: IRWIN LIEBER
                                ------------------------------------------------
                            Title: PRESIDEN
                                  ----------------------------------------------
                            80 Cuttermill Road, Suite 311
                            Great Neck, NY 11021
                            copy to:
                            825 Third Avenue, 32nd Floor
                            New York, NY 10022
                            Attn:  Lawrence Wagenberg
                            Facsimile:  (   )

                            WHEATLEY ASSOCIATES III, L.P.

                            By:  Wheatley Partners III LLC, its
                            General Partner

                            By:/S/ IRWIN LIEBER
                               -------------------------------------------------
                            Name: IRWIN LIEBER
                                 -----------------------------------------------
                            Title: PRESIDENT
                                  ----------------------------------------------
                            Same address as above

                            WHEATLEY FOREIGN PARTNERS III, L.P.

                            By:  Wheatley Partners III LLC, its
                            General Partner

                            By:/S/ IRWIN LIEBER
                               -------------------------------------------------
                            Name: IRWIN LIEBER
                                 -----------------------------------------------
                            Title: PRESIDENT
                                   ---------------------------------------------
                            Same address as above

                                                              PURCHASE AGREEMENT
<PAGE>

                            UBS CAPITAL AMERICAS II, LLC

                            By:  UBS Capital Americas, LLC, as advisor

                            By:/S/ ILLEGIBLE
                               -------------------------------------------------
                            Name:
                                 -----------------------------------------------
                            Title:
                                  ----------------------------------------------

                            By:/S/ MARC UNGER
                               -------------------------------------------------
                            Name: MARC UNGER
                                 -----------------------------------------------
                            Title: CHIEF FINANCIAL OFFICER
                                   ---------------------------------------------
                            299 Park Avenue, 34th Floor
                            New York, NY 10171
                            Fax:  (212) 821-6333

                                                              PURCHASE AGREEMENT
<PAGE>

                            AMAN VENTURES

                            By:/S/ WILLIAM J. BELL
                               -------------------------------------------------
                            Name: WILLIAM J. BELL
                                  ----------------------------------------------
                            Title: MANAGING PARTNER
                                  ----------------------------------------------
                            1500 Owl Creek Ranch Road
                            Aspen, CO  81611
                            Fax:  (970) 923-8855

                                                              PURCHASE AGREEMENT
<PAGE>

                            /S/ BILL RUSHER
                            ----------------------------------------------------
                            Bill Rusher
                            142 Sansome Street, 5th Floor
                            San Francisco, CA 94104
                            Fax:415-397-2842

                            /S/ FRANK JUSKA
                            ----------------------------------------------------
                            Frank Juska
                            142 Sansome Street, 5th Floor
                            San Francisco, CA 94104
                            Fax

                            /S/ MARC FRANCIS
                            ----------------------------------------------------
                            Mark Francis
                            765 Park Avenue
                            New York, NY  10021
                            Fax:  212-816-2176

                                                              PURCHASE AGREEMENT
<PAGE>

                            HFI PRIVATE EQUITY LTD.

                            By: /S/ T. BOGGESS
                                ------------------------------------------------
                            Name: T. BOGGESS
                                  ----------------------------------------------
                            Title: ALTERNATE DIRECTOR
                                   ---------------------------------------------

                            By: /S/ DAVID W.J. ATWOOD
                                ------------------------------------------------
                            Name: DAVID W.J. ATWOOD
                                  ----------------------------------------------
                            Title: ALTERNATE DIRECTOR
                                   ---------------------------------------------
                            Clarenden House
                            2 Church Street
                            Hamilton HM CX
                            Bermuda

                                                              PURCHASE AGREEMENT
<PAGE>

                                   SCHEDULE A

                                   PURCHASERS
<TABLE>
<CAPTION>
NAME AND ADDRESS OF PURCHASER                      NUMBER OF SHARES         PRICE
-----------------------------                      ----------------         -----
<S>                                                     <C>              <C>
Putnam OTC and Emerging Growth Fund                     1,277,547        $ 3,999,999.66
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

TH Lee, Putnam Investment Trust                         1,916,321        $ 6,000,001.05
TH Lee, Putnam Emerging Opportunities Portfolio
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

Putnam Funds Trust - Putnam Technology Fund               319,387        $ 1,000,000.70
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

Van Wagoner Private Opportunities Fund, L.P.              638,774        $ 2,000,001.39
345 California Street
Suite 2450
San Francisco, CA 94104

Van Wagoner Crossover Fund, L.P.                          638,774        $ 2,000,001.39
345 California Street
Suite 2450
San Francisco, CA 94104

Wheatley Partners III                                     446,162        $ 1,396,933.22
80 Cuttermill Road, Suite 311
Great Neck, NY 11021
copy to:
825 Third Avenue, 32nd Floor
New York, NY 10022
Attn:  Lawrence Wagenberg

Wheatley Associates III                                    95,860        $   300,137.66
address same as above
</TABLE>

                                                              PURCHASE AGREEMENT
                                      A-1

<PAGE>

<TABLE>
<CAPTION>
NAME AND ADDRESS OF PURCHASER                      NUMBER OF SHARES         PRICE
-----------------------------                      ----------------         -----
<S>                                                     <C>              <C>
Wheatley Foreign Partners III                              96,752        $   302,930.51
address same as above

UBS Capital Americas II, LLC                              638,774        $ 2,000,001.39
299 Park Avenue, 34th Floor
New York, NY 10171

HFI Private Equity Ltd                                    373,106        $ 1,168,194.89
Clarenden House, 2 Church Street
Hamilton HM CX
Bermuda

Aman Ventures                                             245,352        $   768,197.11
1500 Owl Creek Ranch Road
Aspen, CO  81611

Mark Francis                                                6,388        $    20,000.83
765 Park Avenue
New York, NY  10021

EMC Investment Corporation                                638,774        $ 2,000,001.39
35 Parkwood Drive
Hopkinton, MA  01748

DRW Ventures                                                7,128        $    22,317.77
60 South 6th Street
Minneapolis, MN 55402

Bill Rusher                                                 1,003        $     3,140.39
142 Sansome Street, 5th Floor
San Francisco, CA 94104

Frank Juska                                                 1,003        $     3,140.39
142 Sansome Street, 5th Floor
San Francisco, CA 94104

TOTAL SERIES CC                                         7,341,105        $22,984,999.76
</TABLE>

                                                              PURCHASE AGREEMENT
                                      A-2

<PAGE>

                                   SCHEDULE B

                                  SUBSIDIARIES

CommVault Systems (Canada) Inc., a Canadian corporation
CommVault Systems Mexico S de RL de CV, a Mexican company
CommVault Holding Company BV, a Netherlands company
CommVault Systems Netherlands BV, a Netherlands company

                                                              PURCHASE AGREEMENT
                                      B-1

<PAGE>
                                   SCHEDULE C

         1. Employment Agreement, dated as of January 20, 1999 and amended as of
May 3, 2001, between the Company and N. Robert Hammer, under which Mr. Hammer
has received options to purchase 5,622,400 shares of common stock.

         2. Corporate Change of Control Agreements, between the Company and (i)
Louis Miceli, (ii) Brian McAteer, (iii) Larry Cormier, (iv) Al Bunte; (v) David
West; (vi) Bernardus Veldhoen and (vii) William Beattie.

         3. Stock Plan dated as of May 22, 1996, pursuant to which the Company
is authorized to issue options to purchase 12,950,000 shares of its common stock
of which 12,157,406 shares have been granted.

         4. The Company entered into an agreement with Northern Concepts
Incorporated ("NCI"), dated as of May 2000 pursuant to which 285,000 shares of
the Company's common stock was issued in consideration for the acquisition of
the business of NCI by the Company.

         5.Preferred Stockholders have (i) conversion rights, pursuant to the
Amended Certificate, and (ii) preemptive rights pursuant to (a) the
Stockholders' Agreement; (b) the Series AA Purchase Agreement and (c) the Series
BB Purchase Agreement.

         6. A Warrant to purchase up to 2,616,933 shares of common stock was
issued to Microsoft Corporation in connection with the Series AA Purchase
Agreement.

         7. A Warrant to purchase up to 4,464,536 shares of common stock was
issued to EMC Investment Corporation in connection with the Series BB Purchase
Agreement.

                                                              PURCHASE AGREEMENT
                                      C-1

<PAGE>

                                   SCHEDULE D

                         CORPORATE COMPLIANCE AGREEMENT
              EMPLOYEE INVENTION, CONFIDENTIALITY, NON-COMPETITION,
                      NON-SOLICITATION AND ETHICS AGREEMENT

         THIS AGREEMENT is made between me, the undersigned, and CommVault
Systems, Inc. and on behalf of CommVault Systems, Inc. and its affiliated
companies as they exist from time to time (hereafter referred to collectively as
"CommVault"), and in consideration of my employment by CommVault and in
consideration for the compensation to be paid to me in connection with this
employment:

         1. DUTIES. I shall render faithful and efficient services to CommVault
and perform exclusively for CommVault such duties as may be designated by
CommVault from time to time, which may include the functions of inventing,
discovering and developing new and novel devices, methods, and principles
relating to the business, research, and development of CommVault.

         2. DISCLOSURE OF INVENTIONS. I shall promptly disclose to CommVault in
writing all inventions (including, but not limited to, new contributions,
concepts, ideas, developments, discoveries, processes, formulas, methods,
compositions, techniques, articles, machines, and improvements), all original
works of authorship and all related know-how ("Inventions"), whether or not
patentable, copyrightable or protectable as trade secrets, conceived or made by
me, alone or with others, during the period of my employment with CommVault and,
in the case of clauses (b) and (c) below, during the period of my employment by
CommVault and at any time after I cease to be employed by CommVault for whatever
reason, which (a) relate in any manner to the actual or anticipated business,
research, or development of CommVault, (b) are developed using equipment,
supplies, facilities, trade secret or confidential information of CommVault, or
(c) result from work performed by me or work supervised by me for CommVault.

         3. ASSIGNMENT OF INVENTIONS. I shall assign and do hereby assign to
CommVault my entire rights to each Invention described in SECTION 2 hereof. As
requested by CommVault, I will take all steps reasonably necessary to assist
CommVault in obtaining and enforcing any patent, copyright, or other protection
which CommVault elects to obtain or enforce, in any country, for the Inventions
which I assign to CommVault. I will take no action to jeopardize CommVault's
ability to obtain or enforce its rights in such Inventions. My obligation to
assist CommVault in obtaining and enforcing patents, copyrights, and other
protections shall continue beyond the termination of my employment by CommVault
for whatever reason, but CommVault shall compensate me at a reasonable rate
after the termination of my employment for time actually spent at CommVault's
request providing such assistance. If CommVault is unable, after reasonable
effort, to secure my signature on any document needed to apply for, prosecute,
or enforce any patent, copyright, or other protection in relation to an
Invention, whether because of my physical or mental incapacity or for any other
reason

                                                              PURCHASE AGREEMENT
                                      C-2

<PAGE>

whatsoever, I hereby irrevocably designate and appoint CommVault and its duly
authorized officers and agents as my agent and attorney-in-fact, to act for and
in my behalf and stead to execute and file any such document and to do all other
lawfully permitted acts to further the prosecution and enforcement of patents,
copyrights, or similar protections with the same legal force and effect as if
executed by me.

         4. COMMVAULT CONFIDENTIAL INFORMATION. Because of my employment by
CommVault, I will have access to and will learn techniques, know-how, or other
information of a confidential nature concerning CommVault's experimental and
development work, trade secrets, procedures, business matters or affairs,
including, but not limited to, information relating to inventions, disclosures,
processes, systems, methods, formulas, patents, patent applications, machinery,
materials, research activities and plans, grant proposals, costs of production,
contract forms, prices, business plans, strategies, competitive strengths and
weaknesses, volume of sales, promotional methods, and lists of names or classes
of customers, as well as information of a confidential nature received from
CommVault's customers, joint ventures, collaborators, etc., and information
developed solely or jointly by me, included in connection with Inventions
("CommVault Confidential Information"). Information shall, for purposes of this
Agreement, be considered to be confidential if not known by the trade generally,
even though such information has been disclosed to one or more third parties
pursuant to distribution agreements, joint research agreements, other agreements
or collaborations entered into by CommVault.

         5. PROTECTION OF COMMVAULT CONFIDENTIAL INFORMATION. I shall at all
times use my best efforts and exercise utmost diligence to protect and guard
CommVault Confidential Information. I will not use CommVault Confidential
Information for personal gain or for any purpose outside of my employment by
CommVault or disclose any such information to any person or entity either during
or subsequent to my employment, without CommVault's prior written consent,
except to such an extent as may be necessary in the ordinary course of
performing my duties as an employee of CommVault.

         6. USE OF COMMVAULT CONFIDENTIAL INFORMATION. I shall not, for my own
account or as an officer, member, employee, consultant, representative, or
advisor of another, during my employment with CommVault or at any time
thereafter for any reason whatsoever, engage in or contribute my knowledge to
engineering, development, manufacture, research, business analysis or sales
relating to any product, equipment, process, or material that relates in any way
to the actual or anticipated business or research and development of CommVault,
without the written permission of CommVault. However, the foregoing provision
shall not prohibit me from engaging in any work at any time after leaving the
employ of CommVault, PROVIDED, that CommVault Confidential Information is not
involved in such work AND I am not in violation of any other term of this
Agreement or any other agreement entered into between me and CommVault. The
provisions of this SECTION 6 shall not be construed as limiting to any extent my
continuing obligations pursuant to the provisions in SECTION 5.

                                                              PURCHASE AGREEMENT
                                      C-3

<PAGE>

         7. IMPROPER USE OR DISCLOSURE OF CONFIDENTIAL INFORMATION. I shall not,
during my employment with CommVault, or at any time thereafter, improperly use
or disclose any proprietary information or trade secrets of any former or
current employer or other person or entity and I will not possess or bring onto
the premises of CommVault any such proprietary information without the prior
written consent of such employer, person or entity.

         8. OTHER RESTRICTIONS ON EMPLOYEE. I represent that there are no other
agreements or requirements to assign any invention or discovery conceived or
made by me, alone or with others, unless I have so indicated at the end of this
Agreement.

         9. DISCLOSURE IF INVENTIONS. I represent that I have listed and
described in detail at the end of this Agreement all inventions, if any,
patented and unpatented, which I conceived or made PRIOR to my employment by
CommVault. Any invention not so listed and described shall be presumed to have
been made during my employment by CommVault.

         10. RETURN OF COMMVAULT COMPANY INFORMATION. Upon termination of my
employment with CommVault for any reason, I shall disclose and provide to
CommVault all originals and all copies which are in my possession or under my
control, of all notes, memoranda, records, reports, drawings, blueprints, codes,
programs. Software, manuals, materials and data of any nature which are the
property of CommVault, which shall include, but not be limited to, every item in
my possession or under my control which contains any CommVault Confidential
Information.

         11. NON-COMPETITION AND NON-SOLICITATION. I acknowledge that because my
knowledge of the CommVault Confidential Information and the personal contacts
with the customers and employees of CommVault acquired by me during my
employment, CommVault would be irreparably damaged should I, in any manner or
form, enter into any form of competition with CommVault. I, therefore agree that
at all times during my employment and for a period of TWELVE (12) MONTHS
thereafter, I will not directly or indirectly, in any individual or
representative capacity, carry on, engage or participate in any business that is
in competition in any manner whatsoever with the business of CommVault, except
as expressly provided for in this Agreement, or as may hereafter be expressly
agreed to in writing by CommVault. Further, I agree to not directly or
indirectly hire, seek to hire, or refer for other employment any current
employee of CommVault nor will I, in any manner or capacity, directly or
indirectly: divert or attempt to divert from CommVault, through any means
whatsoever, any business or customers of CommVault, during the TWELVE (12) MONTH
period following my termination of employment. The phrase "carry on, engage or
participate in any business that is in competition in any manner whatsoever with
the business of CommVault" shall include, but not be limited to, the doing by
you or by any person, firm, corporation, association or other entity that
directly or indirectly, through one or more intermediaries, is controlled by, or
is under common control with, or controls you, of any of the following acts
other than as related to your services to CommVault pursuant to your employment
with CommVault: carrying on, engaging in or participating in any such business
as a principal, for your own account or solely, or jointly with others as a

                                                              PURCHASE AGREEMENT
                                      C-4

<PAGE>

partner (general or limited), joint venturer, shareholder or holder of any
equity security of any other corporation or entity, or as a consultant,
contractor, or subcontractor or agent of or for any person, firm, corporation,
association, or other entity or through any agency or by any other means
whatsoever; or utilizing for your own benefit, or making available to any
person, firm, corporation, association or other entity, any confidential or
proprietary proposals, financial statements, governmental filings, cost data,
business plans or correspondence relating to such information, or other
CommVault Confidential Information. I acknowledge and agree that, in light of
the nature of the business of CommVault, the foregoing activity and time period
restrictions are reasonable and properly required for the adequate protection of
CommVault, and that, in the event any such activity or time period restriction
is deemed to be unreasonable or unenforceable by a court of competent
jurisdiction, then I agree to submit to the reduction of such activity or time
period restriction to the extent necessary to enable the court to enforce such
restrictions to the fullest extent permitted under applicable law. It is the
desire and intent of the parties that the provisions of this Agreement shall be
enforced to the fullest extent permissible under the laws and public policies
applied by any jurisdiction where enforcement is sought.

         12. ETHICS. I understand and agree at all times to: (a) follow the
policies and guidelines of CommVault, as set forth by CommVault from time to
time; (b) represent CommVault in a professional manner exhibiting appropriate
behavior consistent with the highest ethical standards; (c) not make any
disparaging comment or statement (written or oral) about CommVault; (d) comply
with all applicable federal, state, and local laws, ordinances, regulations and
codes, including all Security and Exchange Commission laws and regulations; and,
(e) to apply for national security or other governmental clearance, if requested
by CommVault.

         13. GENERAL

         (a) I understand and agree that the restrictions of this Agreement are
limited only to those restrictions necessary for the adequate and legitimate
protection of CommVault. Each paragraph and subparagraph of this document is
separate from each other and constitutes a separate and distinctive covenant. In
the event any limitation hereunder is deemed to be unreasonable by a court of
competent jurisdiction, then I agree to submit to the reduction of such
limitation as the court shall deem reasonable. In the event that I am in
violation of any limitation herein, then the time limitation shall be extended
for a period of time equal to the period of time during which such breach should
occur.

         (b) I understand that nothing in this Agreement shall confer upon me
any right to continue in the employ of CommVault. I understand that the
restrictions contained in this Agreement shall survive the termination of my
employment with CommVault for any reason.

         (c) I certify that I have not entered into, and I agree to not enter
into any agreement, either written or oral, in conflict with this Agreement.

                                                              PURCHASE AGREEMENT
                                      C-5
<PAGE>

         (d) I hereby authorize CommVault to notify others, including, without
limitation, customers of CommVault and my future employers, of the terms of this
Agreement and my responsibilities hereunder.

         (e) This Agreement shall be governed by the laws of the State of New
Jersey, without regard to New Jersey choice of law principles, and adjudicated
in the courts located in the State of New Jersey. Each paragraph and
subparagraph shall be independent and separable from all other paragraphs and
subparagraphs, and the invalidity of a paragraph and subparagraph shall not
affect the enforceability of any of the other paragraphs and subparagraphs. For
purposes of this Agreement, the business of CommVault shall include the business
of any corporation, firm, or partnership, directly or indirectly, controlled by,
controlling, or under common control with CommVault or any partner or joint
venturer of CommVault. For any violation of this Agreement, a restraining order
and/or an injunction may be issued against me in addition to any other rights
CommVault may have under applicable law. In the event any party to this
Agreement is successful in any suit or proceeding brought or instituted with
respect to this Agreement or to enforce the Agreement, the prevailing party will
be paid by the losing party, in addition to other costs and damages, reasonable
attorney's fees and costs.

         (f) This Agreement shall be effective during the period of my
employment by CommVault and for any periods thereafter as set forth herein,
inure to the benefit of any successor or assignee of CommVault, and be binding
upon my heirs, administrators, and representatives.

I acknowledge that I am entering into this Agreement knowingly and voluntarily,
and that I have had an opportunity to review it with counsel of my choosing.

------------------------------------
Employee Signature

Dated:
      ------------------------------

USE THE SPACE BELOW AND THE BACK OF THIS AGREEMENT (IF NECESSARY) TO LIST ANY
AND ALL INVENTIONS CONCEIVED OR MADE BY ME PRIOR TO MY EMPLOYMENT WITH
COMMVAULT, AND A DETAILED DESCRIPTION THEREOF, AND OTHER AGREEMENTS OR
REQUIREMENTS TO ASSIGN INVENTIONS OR DISCOVERIES, AS DESCRIBED IN SECTIONS 8 AND
9 ABOVE.

                                                              PURCHASE AGREEMENT
                                      C-6<PAGE>

                                                                   Exhibit 10.17

                          SERIES CC PURCHASE AGREEMENT

                  THIS SERIES CC PURCHASE AGREEMENT (this "AGREEMENT"), dated as
of September 2, 2003, is by and between the parties listed on SCHEDULE A hereto
(collectively , the "PURCHASERS") and CommVault Systems, Inc., a Delaware
corporation (the "COMPANY").

                  WHEREAS, each of the Purchasers desire to invest in the
Company; and

                  WHEREAS, the Company desires to issue and sell to the
Purchasers an aggregate of 4,790,802 shares of its Series CC Preferred Stock
(the "SHARES") and the Purchasers desire to purchase the Shares on the terms and
subject to the conditions described herein.

                  NOW, THEREFORE, in consideration of the premises and of the
mutual covenants, agreements and warranties herein contained, the parties hereto
agree as follows:

                  1. DEFINITIONS. Capitalized terms that are not defined in the
text of this Agreement have the meanings set forth below:

         "Additional Shares" has the meaning set forth in SECTION 5(E).

         "Affiliate" shall mean, with respect to any specified Person, any other
Person which, directly or indirectly, owns, manages or controls, is under common
ownership, management or control with, or is owned, managed or controlled by,
such specified Person and, with respect to Putnam, any funds or accounts where
Putnam Investment Management, LLC or its affiliates, acts as Investment Adviser
(as defined in the Investment Advisers Act of 1940, as amended). For purposes of
this definition, a Person shall be deemed to control another Person if the first
Person owns, manages or holds more than 50% of the voting power of the second
Person.

         "Amended Certificate" shall mean the Amended and Restated Certificate
of Incorporation of the Company in the form of EXHIBIT 2.

         "Board of Directors" shall mean the board of directors of the Company.

         "Closing" has the meaning set forth in SECTION 2(B).

         "Code" shall mean the Internal Revenue Code of 1986 or any successor
statute, and the rules and regulations thereunder, collectively and as from time
to time amended and in effect.

         "Commission" shall mean the Securities and Exchange Commission.

         "Conversion Shares" has the meaning set forth in SECTION 5(C).

         "Environmental Laws" has the meaning set forth in SECTION 3(R).

         "ERISA" shall mean the Employee Retirement Income Security Act of 1974
or any successor statute and the rules and regulations thereunder, collectively
and as from time to time amended and in effect.

                                      -1-

<PAGE>

         "Existing Series CC Purchase Agreement" means the Series CC Purchase
Agreement, dated as of February 14, 2002, between the Company and the other
Persons party thereto.

         "Existing Series CC Registration Rights Agreement" means the
Registration Rights Agreement, dated as of February 14, 2002, between the
Company and the holders of the Series CC Preferred Stock party thereto.

         "Financial Statements" has the meaning set forth in SECTION 3(G).

         "Governmental Authority" shall mean the government of the United States
or any foreign country or any state or political subdivision thereof and any
entity, body or authority exercising executive, legislative, judicial,
regulatory or administrative functions of or pertaining to government.

         "Initial Public Offering" shall mean the initial public offering or
sale of common stock by the Company through underwriters or otherwise, that
requires registration, qualification or the filing of a prospectus under the
Securities Act.

         "Issuance Notice" has the meaning set forth in SECTION 5(E).

         "Knowledge" shall mean the actual knowledge (assuming reasonable
investigation) of N. Robert Hammer, Louis Miceli, Larry Cormier, Al Bunte and
Brian McAteer and the other senior executives of the Company.

         "Law" shall mean any law, statute, regulation, ordinance, rule, order,
decree, judgment, consent decree, settlement agreement or governmental
requirement enacted, promulgated, entered into, agreed or imposed by any
Governmental Authority.

         "Lien" shall mean any mortgage, lien (except for any lien for taxes not
yet due and payable), charge, restriction, pledge, security interest, option,
lease or sublease, claim, right of any third party, easement, encroachment or
encumbrance.

         "Litigation" has the meaning set forth in SECTION 3(E).

         "Material Adverse Effect" shall mean an effect on the business,
operations, assets, liabilities, results of operations, cash flows or condition
(financial or otherwise) of the Company which is material and adverse.

         "Non-Preemptive Shares" shall mean any voting shares of the capital
stock of the Company issued, sold, granted or conveyed (i) as consideration in
any acquisition of all or a portion of any Person or a merger or combination
with any Person duly authorized by the Board of Directors, (ii) to any current
or new director, officer, employee or consultant of the Company pursuant to any
plan or arrangement, now or hereafter existing, duly authorized by the Board of
Directors, (iii) any shares of capital stock issued in connection with the
antidilution rights of any Person or (iv) pursuant to any of the items listed on
SCHEDULE C.

                                      -2-

<PAGE>

         "Person" shall mean any individual, corporation, proprietorship, firm,
partnership, limited liability company, limited partnership, trust, association,
Massachusetts business trust or other entity.

         "Preferred Stock" shall mean, collectively, the Company's issued and
outstanding Series A Preferred Stock, Series B Preferred Stock, Series C
Preferred Stock, Series D Preferred Stock, Series E Preferred Stock, Series AA
Preferred Stock, Series BB Preferred Stock and Series CC Preferred Stock.

         "Proprietary Assets" has the meaning set forth in SECTION 3(F).

         "Proprietary Software" has the meaning set forth in SECTION 3(F).

         "Purchase Price" has the meaning set forth in SECTION 2(A).

         "Putnam" means funds and accounts managed by Affiliates of Putnam
Investments, LLC.

         "Registration Rights Agreement" shall mean the Amended and Restated
Series CC Registration Rights Agreement (amending and restating the Existing
Series CC Registration Rights Agreement) to which Purchasers shall become a
party as of the Closing in the form of EXHIBIT 1.

         "Required Consents" means (i) the approval of the Amended Certificate
by the Company's stockholders and the filing of such certificate with the
Delaware Secretary of State, (ii) approval of amendments to the Series AA
Registration Rights Agreement, the Series BB Registration Rights Agreement, the
Existing Series CC Registration Rights Agreement and the Stockholders' Agreement
and (iii) waivers by the holders of the Company's Preferred Stock of preemptive
rights to purchase the Shares.

         "Response Notice" has the meaning set forth in SECTION 5(E).

         "Securities Act" shall mean the Securities Act of 1933, as amended.

         "Series AA Purchase Agreement" shall mean the Purchase Agreement, dated
as of April 14, 2000 between the Company and the other Persons party thereto.

         "Series AA Registration Rights Agreement" shall mean the Amended and
Restated Registration Rights Agreement, dated as of February 14, 2002, between
the Company and the holders of the Company's Series AA Preferred Stock.

         "Series BB Purchase Agreement" shall mean the Purchase Agreement, dated
as of November 10, 2000, by and between the Company and the other Persons party
thereto.

         "Series BB Registration Rights Agreement" shall mean the Amended and
Restated Registration Rights Agreement, dated as of February 14, 2002, between
the Company and the holders of the Series BB Preferred Stock.

         "Share" has the meaning set forth in the preamble.

                                      -3-

<PAGE>

         "Stock Plan" shall mean the Company's stock plan, as described on
SCHEDULE C.

         "Stockholders' Agreement" shall mean the stockholders' agreement, dated
as of May 22, 1996, and as further amended, between the Company and certain of
its stockholders.

         "Subsidiaries" shall mean the Persons set forth on SCHEDULE B.

         "Third Party Buyer" has the meaning set forth in SECTION 5(E).

         "Transfer" has the meaning set forth in SECTION 5(D).

                  2. PURCHASE AND SALE OF SHARES.

         (a) PURCHASE PRICE. Subject to the terms and conditions set forth in
this Agreement, at the Closing (as hereinafter defined), the Purchasers shall
purchase, and the Company shall issue and sell to the Purchasers the Shares for
an aggregate purchase price (the "Purchase Price") of $15,000,001.06. The number
of Shares being sold to each Purchaser and the portion of the Purchase Price
attributable thereto is set forth on SCHEDULE A hereto.

         (b) CLOSING. The closing (the "Closing") of the transactions described
herein shall occur at 10:00 a.m. on the date hereof, at the offices of Mayer,
Brown, Rowe & Maw LLP, 190 S. LaSalle Street, Chicago, IL 60603, or such other
place and time as agreed upon by the Purchasers and the Company. At the Closing,
the Purchasers shall pay the Company the Purchase Price in cash by wire transfer
of immediately available funds to an account designated by the Company, which
designation shall occur at least two business days before the Closing, and the
Company shall deliver to each Purchaser a certificate representing the Shares
purchased by such Purchaser; PROVIDED, that, if so requested by a Purchaser that
is an Affiliate of Putnam, the Company will deliver such certificate to such
Purchaser's custodian at least one business day prior to the Closing pursuant to
an escrow arrangement reasonably acceptable to such custodian, the Company and
Putnam.

                  3. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company
hereby represents and warrants to each of the Purchasers:

         (a) DUE INCORPORATION; SUBSIDIARIES. Each of the Company and the
Subsidiaries is duly incorporated, validly existing and in good standing under
the laws of its jurisdiction of incorporation, with all requisite power and
authority to own, lease and operate its properties and to carry on its business
as they are now being owned, leased, operated and conducted. Each of the Company
and the Subsidiaries is licensed or qualified to do business and is in good
standing as a foreign corporation in each jurisdiction where the nature of the
properties owned, leased or operated by it and the businesses transacted by it
require such licensing or qualification, except where the failure to be so
licensed or qualified would not individually or in the aggregate have a Material
Adverse Effect. Except as set forth on SCHEDULE B, the Company has no direct or
indirect subsidiaries, either wholly or partially owned, and the Company does
not hold any direct or indirect economic, voting or management interest in any
Person or directly or indirectly own any security issued by any Person. Each
Subsidiary is wholly owned by the Company.

                                      -4-

<PAGE>

                  (b) DUE AUTHORIZATION. The Company has full power and
authority to enter into this Agreement and the Registration Rights Agreement and
to consummate the transactions contemplated hereby and thereby. The execution,
delivery and performance by the Company of this Agreement and the Registration
Rights Agreement have been duly and validly approved by the board of directors
of the Company and no other actions or proceedings on the part of the Company
are necessary to authorize this Agreement, the Registration Rights Agreement and
the transactions contemplated hereby and thereby. The Company has duly and
validly executed and delivered this Agreement and has duly and validly executed
and delivered the Registration Rights Agreement. This Agreement constitutes
legal, valid and binding obligations of the Company and the Registration Rights
Agreement upon execution and delivery by the Company will constitute legal,
valid and binding obligations of the Company, in each case, enforceable in
accordance with their respective terms, except as such enforceability may be
limited by applicable bankruptcy, insolvency, moratorium, reorganization or
similar laws in effect which affect the enforcement of creditors' rights
generally and by equitable limitations on the availability of specific remedies.

         (c) CONSENTS AND APPROVALS; AUTHORITY RELATIVE TO THIS AGREEMENT.

                  (i) No consent, authorization or approval of, filing or
registration with, or cooperation from, any Governmental Authority or any other
Person not a party to this Agreement that has not been received by the Company
is necessary in connection with the execution, delivery and performance by the
Company of this Agreement and the execution, delivery and performance by the
Company of the Registration Rights Agreement or the consummation of the
transactions contemplated hereby or thereby (including, without limitation, the
offer, issuance, sale and delivery of the Shares and the Conversion Shares).

                  (ii) The execution, delivery and performance by the Company of
this Agreement and the Registration Rights Agreement or the consummation of the
transactions contemplated hereby and thereby do not and will not (1) violate any
Law; (2) violate or conflict with, result in a breach or termination of,
constitute a default or give any third party any additional right (including a
termination right) under, permit cancellation of, result in the creation of any
Lien upon any of the assets or properties of the Company under, or result in or
constitute a circumstance which, with or without notice or lapse of time or
both, would constitute any of the foregoing under, any contract to which the
Company, is a party or by which the Company or any of its assets or properties
are bound; (3) permit the acceleration of the maturity of any indebtedness of
the Company or indebtedness secured by its assets or properties; or (4) violate
or conflict with any provision of any of the Amended Certificate or by-laws of
the Company.

         (d) CAPITALIZATION.

                  (i) The authorized capital stock of the Company is as
described in the Amended Certificate. The outstanding capital stock of the
Company immediately prior to the Closing and before the issuance of the Shares
is as follows: (i) 2,039,717 shares of Series A Preferred Stock, (ii) 346,000
shares of Series B Preferred Stock, (iii) 333,333 shares of Series C Preferred
Stock, (iv) 247,204 shares of Series D Preferred Stock, (v) 200,000 shares of
Series E Preferred Stock, (vi) 4,361,555 shares of Series AA Preferred Stock,
(vii) 2,758,358 shares of

                                      -5-
<PAGE>

Series BB Preferred Stock, (viii) 7, 341,105 shares of Series CC Preferred Stock
and (ix) 39,786,975 shares of Common Stock. All of the outstanding capital stock
of the Company and each Subsidiary (i) is validly issued, fully paid and
nonassessable and (ii) is free of preemptive rights (except as provided in the
Stockholders' Agreement, Series AA Purchase Agreement, the Series BB Purchase
Agreement, the Existing Series CC Purchase Agreement and this Agreement). When
issued, the Shares and the Conversion Shares will be validly issued, fully paid
and nonassessable and will not have been issued in violation of any preemptive
rights or rights of first refusal. The authorized capital stock as described in
the Amended Certificate contains a sufficient number of shares of common stock
for issuance of the Conversion Shares.

                  (ii) Except as set forth above or on SCHEDULE C, there are no
shares of capital stock or other securities (whether or not such securities have
voting rights) of the Company issued or outstanding or any subscriptions,
options, warrants, calls, rights, convertible securities or other agreements or
commitments of any character obligating the Company to issue, transfer or sell,
or cause the issuance, transfer or sale of, any shares of its capital stock or
other securities (whether or not such securities have voting rights). Except as
set forth in SCHEDULE C, there are no outstanding contractual obligations of the
Company which relate to the purchase, sale, issuance, repurchase, redemption,
acquisition, transfer, disposition, holding or voting of any shares of its
capital stock or other securities. After giving effect to the issuance of the
Shares (and antidilution adjustments resulting therefrom), the maximum number of
shares of common stock that the Company has issued and would be obligated to
issue as of the date hereof is 82,877,864 shares on a fully diluted basis.

         (e) LITIGATION.

                  (i) There is no claim, action, suit, investigation or
proceeding ("LITIGATION") pending or, to the Knowledge of the Company,
threatened against the Company or any Subsidiary, or involving any of its
properties or assets by or before any court, arbitrator or other Governmental
Entity which (1) in any manner challenges or seeks to prevent, enjoin, alter or
materially delay the transactions contemplated by this Agreement or (2) if
resolved adversely to the Company or any Subsidiary, would reasonably be
expected to have a Material Adverse Effect.

                  (ii) Neither the Company nor any Subsidiary is in default
under or in breach of any order, judgment or decree of any court, arbitrator or
other Governmental Authority.

         (f) INTELLECTUAL PROPERTY.

                  (i) The Company owns all right, title and interest in, or, to
the Knowledge of the Company, has the right to use: all patents and the
inventions claimed therein; trademarks, service marks and trade names, together
with associated goodwill; copyrights and copyrightable work; Internet domain
names; registrations and applications relating to any of the foregoing;
know-how, processes, formulae, algorithms, models, methodologies and trade
secrets; computer programs, including any and all software implementations of
algorithms, models and methodologies whether in source code or object code form;
databases and compilations, including any and all data, all documentation,
including user manuals and training materials, related to any of the foregoing;
and the content and information contained on any Company Web

                                      -6-

<PAGE>

site; and other confidential and proprietary information (collectively, the
"Proprietary Assets") used in its business as now conducted and as presently
proposed to be conducted. To the Knowledge of the Company, no person or entity
has any ownership right, title, interest, claim in or Lien on any of the
Company's Proprietary Assets. No current or former employee, officer, director
or consultant of the Company has any ownership right, right to use, title,
interest, claim in or Lien on any of the Company's Proprietary Assets. Except
for licenses granted in the ordinary course of business in connection with the
sale of the Company's products, the Company has not granted and, to the
Knowledge of the Company, there are not outstanding, any options, licenses or
agreements of any kind relating to any Proprietary Asset of the Company, nor has
the Company granted and, to the Knowledge of the Company, is the Company bound
by or a party to, any option, license or agreement of any kind with respect to
any of its Proprietary Assets. No settlement agreements, consents, judgments,
orders, forbearance to sue or similar obligations limit or restrict the
Company's rights in and to any Proprietary Assets.

                  (ii) To the Knowledge of the Company, the Company has not
violated, misappropriated, diluted or infringed, and would not, by conducting
its business as currently proposed, violate, misappropriate, dilute or infringe,
any intellectual property right in any Proprietary Asset of any other Person.
There is no claim, action, suit, investigation or proceeding pending or, to the
Knowledge of the Company, threatened against the Company which would affect in
any way any of its Proprietary Assets by or before any court, arbitrator or
other Governmental Entity. To the Knowledge of the Company, no third party has
violated, misappropriated, diluted or infringed any intellectual property right
in any Proprietary Asset of the Company.

                  (iii) The Company takes all reasonable measures to protect the
confidentiality of its trade secrets including requiring third parties having
access thereto to execute written nondisclosure agreements. Each employee of the
Company hired after January 1, 1998 has signed an Employee Inventions and
Confidentiality Agreement substantially in the form attached hereto as SCHEDULE
D.

                  (iv) All material Proprietary Assets owned or used by the
Company have been duly maintained, are valid and subsisting, in full force and
effect and have not been cancelled, expired or abandoned. The execution,
delivery and performance by the Company of this Agreement and the Registration
Rights Agreement, and the consummation of the transactions contemplated hereby
and thereby will not result in the loss or impairment of the Company's rights to
own or use any of the Proprietary Assets, nor will such consummation require the
consent of any third party in respect of any Proprietary Assets.

                  (v) Except for Microsoft Corporation's SQL product, which
Microsoft Corporation has licensed to the Company (with rights to further
sublicense such software), the Company's software products (the "PROPRIETARY
SOFTWARE") were either developed (a) by employees of the Company within the
scope of their employment; (b) by independent contractors as
"works-made-for-hire," as that term is defined under Section 101 of the United
States Copyright Act, 17 U.S.C. ss. 101, pursuant to written agreement; or (c)
by third parties who have assigned all of their rights therein to the Company
pursuant to a written agreement. No former or present employees, officers or
directors of the Company, or any other third parties retain any rights of
ownership or use of the Proprietary Software, and no employees or third parties
who

                                      -7-

<PAGE>

have developed or participated in the development of the Proprietary Software
have any claims to any moral rights therein.

                  (g) FINANCIAL STATEMENTS. The Company has furnished to each of
the requesting Purchasers audited financial statements as of, and for, the year
ended March 31, 2003, including a balance sheet and statement of income
(collectively, the "FINANCIAL STATEMENTS"). The Financial Statements are
complete and correct, are in accordance with the books and records of the
Company and present fairly in all material respects the financial condition and
results of operations of the Company, at the dates and for the periods
indicated, and have been prepared in accordance with generally accepted
accounting principles consistently applied.

                  (h) ABSENCE OF UNDISCLOSED LIABILITIES. The Company does not
have any liability (whether known or unknown and whether absolute or
contingent), except for (a) liabilities shown on the face of the Financial
Statements and (b) liabilities that have arisen since March 31, 2003 in the
ordinary course of business that are not material.

                  (i) ABSENCE OF CHANGES. Since March 31, 2003, the Company has
conducted its business in the ordinary course, consistent with past practice and
there has not been any event or condition which has had or would be reasonably
expected to have, individually or in the aggregate, a Material Adverse Effect.

                  (j) CONTRACTS. The Company does not have and is not bound by
any contract, agreement, lease or commitment, other than (i) contracts for the
purchase of supplies and services or the licensing of technology that were
entered into in the ordinary course of business that do not involve more than
$250,000 per year and do not extend for more than one year, (ii) sales contracts
entered into in the ordinary course of business, (iii) the leases for the
Company's office or other space, (iv) contracts terminable at will by the
Company on no more than 30 days' notice without cost or liability to the
Company, (v) an agreement with Microsoft Corporation, dated as of April 12,
2000, or (vi) other contracts the loss of which would not have a Material
Adverse Effect. The Company has provided the Purchasers with a copy of all its
material contracts. To the Knowledge of the Company, all of the contracts to
which it is a party are valid and binding and are in full force and effect as of
the date of this Agreement.

                  (k) REGISTRATION RIGHTS. Other than the Registration Rights
Agreement, the Series AA Registration Rights Agreement, the Series BB
Registration Rights Agreement, the Existing Series CC Registration Rights
Agreement, the Stockholders Agreement and the piggyback registration rights
granted pursuant to the purchase agreement listed in paragraph 4 of SCHEDULE C,
the Company has not granted any registration rights to any party for any of its
securities.

                  (l) COMPLIANCE WITH LAWS. The Company and each Subsidiary are
in compliance in all material respects with all applicable Laws. All securities
issued by the Company prior to the date hereof have been issued in transactions
exempt from the registration requirements of Section 5 of the Securities Act.

                  (m) OFFERING OF SHARES. Neither the Company nor any Person
acting on its behalf has taken or will take any action (including, without
limitation, any offering of any securities of the Company under circumstances
which would require, under the Securities Act, the integration of

                                      -8-

<PAGE>

such offering with the offering and sale of the Shares) which might reasonably
be expected to subject the offering, issuance or sale of the Shares to the
registration requirements of the Securities Act. Subject to the continuing
accuracy of the Purchasers' representations in Section 4, the offer, sale and
issuance of the Shares and the Conversion Shares in accordance with the terms of
this Agreement and the Amended Certificate constitute or will constitute
transactions exempt from the registration requirements of Section 5 of the
Securities Act.

                  (n) BROKERS. Except for fees and commissions payable to C.E.
Unterberg, Towbin by the Company, no broker, finder or investment banker is
entitled to any brokerage, finder's or other fee or commission from any party in
connection with the transactions contemplated by this Agreement based upon
arrangements made by or on behalf of the Company.

                  (o) INSURANCE COVERAGE. The Company maintains in full force
and effect insurance coverage that the Company reasonably believes to be
adequate against all liabilities, claims and risks against which it is customary
for comparably situated companies to insure.

                  (p) EMPLOYEES. To the Company's Knowledge, no executive, key
employee, or group of employees has any plans to terminate employment with the
Company. The Company is in compliance in all material respects with all
applicable Laws regarding employment and employment practices and terms and
conditions of employment.

                  (q) ERISA. The Company does not have or otherwise contribute
to or participate in any employee benefit plan subject to Title IV of ERISA.

                  (r) ENVIRONMENTAL MATTERS. The Company is not in violation of
any statute, rule, regulation, decision or order of any Governmental Authority
relating to the use, disposal or release of hazardous or toxic substances or
relating to the protection or restoration of the environment or human exposure
to hazardous or toxic substances (collectively, "ENVIRONMENTAL LAWS"), does not
own or operate any real property contaminated with any substance that is subject
to any Environmental Laws, is not liable for any off-site disposal or
contamination pursuant to any Environmental Laws, and is not subject to any
claim relating to any Environmental Laws, which violation, contamination,
liability or claim would individually or in the aggregate have a Material
Adverse Effect; and the Company has no Knowledge of any pending investigation
that might lead to such a claim.

                  (s) AFFILIATED TRANSACTIONS. Other than the Stockholders'
Agreement, the Series AA Purchase Agreement, the Series AA Registration Rights
Agreement, the Series BB Purchase Agreement, the Series BB Registration Rights
Agreement, agreements for certain advisory services with Credit Suisse First
Boston Corporation and/or its Affiliates, the Company's Employment Agreement
with N. Robert Hammer and the side letters with holders of the Company's Series
A through E Preferred Stock dated February 14, 2002, the Company is not, nor has
it been, a party to or bound by any contract, agreement, lease or commitment
with any of the Affiliates of the Company, other than on arms-length terms which
are no less favorable to the Company than those which could be obtained with a
third party which is not an Affiliate of the Company and no Affiliate of the
Company owns or otherwise has any rights to or interests in any asset, tangible
or intangible, which is used in the conduct of the Company's business.

                                      -9-

<PAGE>

                  (t) NO ILLEGAL PAYMENTS. In connection with the conduct of the
Company's business, none of the Company nor any of their directors or officers
nor, to the Company's Knowledge, any of their employees or agents, has (x)
directly or indirectly given or agreed to give any illegal gift, contribution,
payment or similar benefit to any supplier, customer, governmental official or
employee or other person who was, is or may be in a position to help or hinder
the Company (or assist in connection with any actual or proposed transaction) or
made or agreed to make any illegal contribution, or reimbursed any illegal
political gift or contribution made by any other person, to any candidate for
federal, state, local or foreign public office (i) which might subject the
Company to any damage or penalty in any civil, criminal or governmental
litigation or proceeding or (ii) the non-continuation of which has had or might
have a Material Adverse Effect or (y) established or maintained any unrecorded
fund or asset or made any false entries on any books or records for any purpose.

                  (u) DISCLOSURE. The representations and warranties contained
in this Section 3 (including any schedules and exhibits required to be delivered
by the Company to the Purchasers pursuant to this Agreement) and any certificate
furnished or to be furnished by the Company to the Purchasers do not contain and
on the date of the Closing will not contain any untrue statement of a material
fact or omit to state any material fact necessary in order to make the
statements and information contained in this Section 3 not misleading.

                  4. REPRESENTATIONS AND WARRANTIES OF PURCHASERS.  Each of the
Purchasers severally but not jointly hereby represents and warrants to the
Company as follows:

                  (a) DUE INCORPORATION. Such Purchaser, if not an individual,
is duly organized or duly formed, validly existing and in good standing under
the laws of its jurisdiction of organization, with all requisite power and
authority to own, lease and operate its properties and to carry on its business
as they are now being owned, leased, operated and conducted.

                  (b) DUE AUTHORIZATION. Such Purchaser, if not an individual,
has full power and authority to enter into this Agreement and the Registration
Rights Agreement and to consummate the transactions contemplated hereby and
thereby. The execution, delivery and performance by such Purchaser of this
Agreement and the Registration Rights Agreement have been duly and validly
approved by its governing body empowered to authorize the transactions
contemplated by this Agreement and the Registration Rights Agreement and no
other actions or proceedings on the part of such Purchaser are necessary to
authorize this Agreement, the Registration Rights Agreement and the transactions
contemplated hereby and thereby. Such Purchaser, if an individual, has the legal
capacity to enter into this Agreement and the Registration Rights Agreement.

                  (c) DUE EXECUTION; BINDING EFFECT. Such Purchaser has validly
executed and delivered this Agreement and has duly and validly executed and
delivered (or prior to or at the Closing will duly and validly execute and
deliver) the Registration Rights Agreement. This Agreement constitutes legal,
valid and binding obligations of such Purchaser and such Purchaser's Related
Agreements upon execution and delivery by such Purchaser (as applicable) will
constitute legal, valid and binding obligations of such Purchaser, in each case,
enforceable in accordance with their respective terms, except as such
enforceability may be limited by applicable bankruptcy, insolvency, moratorium,
reorganization or similar laws in effect which

                                      -10-

<PAGE>

affect the enforcement of creditors' rights generally and by equitable
limitations on the availability of specific remedies.

         (d) CONSENTS AND APPROVALS; AUTHORITY RELATIVE TO THIS AGREEMENT.

                  (i) No consent, authorization or approval of, filing or
registration with, or cooperation from, any Governmental Authority or any other
Person not a party to this Agreement is necessary in connection with the
execution, delivery and performance by such Purchaser of this Agreement and the
Registration Rights Agreement and the consummation by such Purchaser of the
transactions contemplated hereby and thereby.

                  (ii) The execution, delivery and performance by such Purchaser
of this Agreement and the Registration Rights Agreement do not and will not (1)
violate any Law applicable to such Purchaser; (2) violate or conflict with,
result in a breach or termination of, constitute a default or give any third
party any additional right (including a termination right) under, permit
cancellation of, result in the creation of any Lien upon any of the assets or
properties of such Purchaser under, or result in or constitute a circumstance
which, with or without notice or lapse of time or both, would constitute any of
the foregoing under, any contract to which Purchaser is a party or by which such
Purchaser or any of its assets or properties are bound; (3) permit the
acceleration of the maturity of any indebtedness of such Purchaser or
indebtedness secured by its assets or properties; or (4) if such Purchaser is
not an individual, violate or conflict with any provision of such Purchaser's
organizational documents.

         (e) BROKERS. No broker, lender or investment banker is entitled to any
brokerage, lender's or other fee or commission from any party in connection with
the transactions contemplated by this Agreement based on arrangements made by or
on behalf of such Purchaser.

         (f) PURCHASE FOR INVESTMENT. Such Purchaser is purchasing the Shares
hereunder for investment without any intent of the distribution thereof within
the meaning of the Securities Act.

         (g) ACCREDITED INVESTOR. Such Purchaser is an "accredited investor"
within the meaning of Regulation 501(a) under the Securities Act and is able to
bear the economic risk of acquisition of the Shares, can afford to sustain a
total loss on such investment, and has such knowledge and experience in
financial and business matters that it is capable of evaluating the merits and
risk of the proposed investment. Such Purchaser has been furnished the
opportunity to ask questions of and receive answers from representatives of the
Company concerning the business and financial affairs of the Company.

                  5. COVENANTS.

         (a) AMENDED CERTIFICATE. The Company shall, prior to the Closing, cause
the Amended Certificate to be filed with the Secretary of State of the State of
Delaware.

         (b) COOPERATION. Each of the Purchasers and the Company agrees to use
its reasonable best efforts to take, or cause to be taken, all such further
actions as shall be necessary to make effective and consummate the transactions
contemplated by this Agreement.

                                      -11-

<PAGE>

         (c) RESERVE SHARES. The Company will at all times reserve and keep
available, solely for issuance and delivery upon conversion of the Shares, the
number of shares of common stock from time to time issuable upon conversion of
all Shares at the time outstanding (the "CONVERSION SHARES"). All Conversion
Shares shall be duly authorized and, when issued upon such conversion in
accordance with the Amended Certificate, shall be validly issued, fully paid and
nonassessable.

         (d) RESTRICTIONS ON TRANSFER. The Purchasers will not, prior to the
earlier of (a) December 31, 2005 or (b) the time of the closing of the Initial
Public Offering, sell, transfer, assign, convey, gift, mortgage, pledge,
encumber, hypothecate, or otherwise dispose of, directly or indirectly,
("TRANSFER") any of the Shares or any Conversion Shares except for (i) Transfers
between and among the Purchasers and their Affiliates provided such Transfer is
in accordance with the transfer restrictions applicable to the Shares or the
Conversion Shares under federal and state securities laws and the Affiliate
transferee agrees to be bound by the restrictions applicable to such Shares or
Conversion Shares, including without limitation the agreements set forth in this
SECTION 5(D), and (ii) Transfers (x) pursuant to a bona fide tender or exchange
offer made pursuant to a merger or other agreement approved by the Board of
Directors to acquire securities of the Company, (y) pursuant to any cash merger,
or other business combination transaction to which the Company is a party or
involved in which the common stock of the Company's stockholders is exchanged
for cash upon consummation of such merger or other business combination or (z)
agreed to in writing by the Company. Notwithstanding any other provision of this
SECTION 5(D), no Purchaser shall avoid the provisions of this SECTION 5(D) by
making one or more transfers to one or more Affiliates and then disposing of all
or any portion of such Purchaser's interest in any such Affiliate.

         (e) PREEMPTIVE RIGHT. If at any time the Company desires to issue or
sell any shares of its capital stock or securities convertible, exercisable or
exchangeable for the Company's capital stock (other than Non-Preemptive Shares)
(the "ADDITIONAL SHARES") to any Person, the Company shall give a written notice
(the "ISSUANCE NOTICE") to the Purchasers setting forth the proposed terms of
the sale of such Additional Shares and the quantity of Additional Shares to be
issued, the proposed issuance date and the price at which such Additional Shares
shall be issued. Each of the Purchasers shall have the option to purchase the
number of Additional Shares necessary to maintain such Purchaser's percentage of
issued and outstanding shares of the Company at the time of the Issuance Notice,
which option may be exercised by giving written notice to the Company (the
"RESPONSE NOTICE") within 14 days of the Issuance Notice that contains an
agreement to purchase all or any portion of the Additional Shares to which such
Purchaser is entitled to purchase. Failure by a Purchaser to give the Response
Notice to the Company within such 14-day period shall be deemed to be a
rejection of such option. For a period of 180 days after any Issuance Notice,
the Company shall have the right to issue or sell to any Person (a "THIRD PARTY
BUYER") up to the number of Additional Shares specified in the Issuance Notice
less the number of Additional Shares subscribed for pursuant to duly tendered
Response Notices at the same price and on other terms not materially less
favorable to the Company than as specified in the Issuance Notice. At the time
of the closing of the sale of the Additional Shares to one or more Third Party
Buyers, the Company shall sell to such Purchaser and such Purchaser shall
purchase the Additional Shares that such Purchaser agreed to purchase in the
Response Notice, at the price and on the terms set forth in the Issuance Notice.
If at the end of the 180th day following any Issuance Notice, the Company has
not completed the

                                      -12-

<PAGE>

issuance described in the Issuance Notice, each Purchaser that has provided a
Response Notice shall be released from its obligations thereunder. If the
Company desires to issue or sell Additional Shares, (i) after such 180-day
period, (ii) except in connection with an Initial Public Offering, on terms
materially less favorable to the Company than as specified in the Issuance
Notice, (iii) except in connection with an Initial Public Offering, at a price
less than the price specified in the Issuance Notice or (iv) except in
connection with an Initial Public Offering, in a quantity greater than as
specified in the Issuance Notice, the Company must again comply with this
SECTION 5(E). If the Company desires to take any of the actions set forth in
clauses (ii), (iii) or (iv) of the prior sentence in connection with an Initial
Public Offering, each Purchaser, at its option, shall be released from its
obligations under its Response Notice. The rights and obligations of the parties
pursuant to this SECTION 5(E) shall terminate upon the closing of an Initial
Public Offering.

         (f) COMPLIANCE WITH SECURITIES LAWS. Such Purchaser understands that
the Shares and the Conversion Shares will not be registered under the Securities
Act or applicable state securities laws and agrees not to sell, pledge or
otherwise transfer any of the Shares and Conversion Shares in the absence of
such registration or an opinion of counsel reasonably satisfactory to the
Company that such registration is not required, except that the requirement of a
legal opinion will not apply to transfers by Putnam to any of its Affiliates.
Except as set forth in the Registration Rights Agreement, such Purchaser
acknowledges that the Company is not required to register the Shares or the
Conversion Shares.

                  6. CONDITIONS.

     (a) CONDITIONS TO OBLIGATIONS OF THE PURCHASERS. The obligations of the
Purchasers to consummate the transactions contemplated hereby shall be subject
to the satisfaction or waiver at or prior to the Closing of each of the
following conditions:

                  (i) No statute, rule or regulation or order of any
Governmental Authority shall be in effect which prohibits the consummation of
the transactions contemplated hereby;

                  (ii) The Company shall have performed, satisfied and complied
in all material respects with all of its covenants and agreements set forth in
this Agreement to be performed, satisfied and complied with prior to or at the
Closing;

                  (iii) The representations and warranties of the Company in
Section 3 shall be true and correct in all material respects as of the date of
Closing;

                  (iv) The Company shall have executed and delivered to each of
the Purchasers the Registration Rights Agreement;

                  (v) The Company shall have obtained sufficient waivers of
pre-emptive rights from all holders of capital stock who possess such rights so
as to allow the consummation of the transactions contemplated by this Agreement;

                  (vi) The Amended Certificate shall have been duly filed with
the Secretary of State of the State of Delaware in accordance with the laws of
the State of Delaware and the Amended Certificate shall be in full force and
effect;

                                      -13-

<PAGE>

                  (vii) Mayer, Brown, Rowe & Maw LLP shall have delivered an
opinion in form and substance reasonably satisfactory to Purchasers;

                  (viii) The Company shall have delivered a good standing
certificate for the Company (or a copy thereof) to each of the Purchasers;

                  (ix) The Company shall have received all consents,
authorizations, and approvals necessary to complete the transactions
contemplated hereby, including, without limitation, the Required Consents;

                  (x) The Company shall have delivered to each Purchaser a
certificate of the Company, dated the date of the Closing and executed by the
Chief Executive Officer of the Company, certifying as to the fulfillment of the
conditions specified in Sections 6(a)(ii), (iii), (vi), (xii) and (xiii) of this
Agreement;

                  (xi) The Company shall have delivered to each Purchaser a
certificate of the Company, dated the date of the Closing and executed by the
Secretary of the Company, certifying: (a) the corporate proceedings taken by the
Company's Board of Directors and, if required, stockholders approving this
Agreement and the Registration Rights Agreement and the transactions
contemplated hereby and thereby; (b) the Amended Certificate; and (c) the
By-laws of the Company;

                  (xii) No claim, action, cause of action, suit, litigation,
arbitration, investigation, hearing, charge, complaint, demand, notice or
proceeding to, from, by or before any Governmental Authority shall be pending or
threatened wherein an unfavorable injunction, judgment, order, decree, ruling,
or charge would (i) prevent consummation of any of the transactions contemplated
by this Agreement or (ii) cause any of the transactions contemplated by this
Agreement to be rescinded following consummation (and no such injunction,
judgment, order, decree, ruling, or charge shall be in effect); and

                  (xiii) There shall not have occurred any event, circumstances,
condition, fact, effect, or other matter which has had or would reasonably be
expected to have a Material Adverse Effect.

         (b) CONDITIONS TO OBLIGATIONS OF THE COMPANY. The obligation of the
Company to consummate the transactions contemplated hereby shall be subject to
the satisfaction or waiver at or prior to the Closing of each of the following
conditions:

                  (i) No statute, rule or regulation or order of any court or
administrative agency shall be in effect which prohibits the consummation of the
transactions contemplated hereby;

                  (ii) Each of the Purchasers shall have executed and delivered
to the Company the Registration Rights Agreement;

                  (iii) The representations and warranties of the Purchasers in
Section 4 shall be true and correct in all material respects as of the date of
Closing;

                                      -14-

<PAGE>
                (iv) The Company shall have received the Required Consents; and

                (v) The Purchasers shall have performed, satisfied and complied
in all material respects with all of their covenants and agreements set forth in
this Agreement to be performed, satisfied and complied with prior to or at the
Closing.

                  7. SURVIVAL OF REPRESENTATIONS AND WARRANTIES.

         The representations and warranties of the parties contained in this
Agreement shall expire on the 18-month anniversary of the Closing, except for
those representations and warranties contained in Sections 3(a) through 3(d)
which shall expire on the later of (i) the 18-month anniversary of the Closing
or (ii) the closing of an Initial Public Offering. After the expiration of such
period, any claim by a party based upon any such representation or warranty
shall be of no further force and effect, except to the extent a party has given
notice to the other party of a claim for breach of any such representation or
warranty prior to the expiration of such period, in which event any
representation or warranty to which such claim relates shall survive with
respect to such claim until such claim is resolved. The covenants and agreements
of the parties hereto contained in this Agreement shall survive the Closing
until performed in accordance with their terms.

                  8. RESTRICTIVE LEGENDS.  Each certificate representing any
Shares or Conversion Shares shall bear legends in substantially the following
form:

         THE SECURITIES EVIDENCED BY THIS CERTIFICATE SHALL BE CONVERTIBLE INTO
         THE COMPANY'S COMMON STOCK IN THE MANNER AND ACCORDING TO THE TERMS SET
         FORTH IN THE CERTIFICATE OF INCORPORATION AS AMENDED AND/OR RESTATED
         FROM TIME TO TIME. THE COMPANY IS AUTHORIZED TO ISSUE MORE THAN ONE
         CLASS OR SERIES OF STOCK. AS REQUIRED UNDER DELAWARE LAW, THE COMPANY
         SHALL FURNISH TO ANY HOLDER UPON REQUEST AND WITHOUT CHARGE, A FULL
         SUMMARY STATEMENT OF THE DESIGNATIONS, VOTING RIGHTS, PREFERENCES,
         LIMITATIONS AND SPECIAL RIGHTS OF THE SHARES OF EACH CLASS OR SERIES
         AUTHORIZED TO BE ISSUED BY THE COMPANY SO FAR AS THEY HAVE BEEN FIXED
         AND DETERMINED AND THE AUTHORITY OF THE BOARD OF DIRECTORS TO FIX AND
         DETERMINE THE DESIGNATIONS, VOTING RIGHTS, PREFERENCES, LIMITATIONS AND
         SPECIAL RIGHTS OF THE CLASSES AND SERIES OF SECURITIES OF THE COMPANY.

         THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "1933 ACT"), OR UNDER
         ANY APPLICABLE STATE LAWS. THE SHARES REPRESENTED BY THIS CERTIFICATE
         HAVE BEEN ACQUIRED BY THE REGISTERED OWNER HEREOF FOR INVESTMENT AND
         NOT WITH A VIEW TO OR FOR SALE IN CONNECTION WITH ANY DISTRIBUTION
         THEREOF WITHIN THE MEANING OF THE 1933 ACT.

                                      -15-

<PAGE>

         THE SHARES MAY NOT BE SOLD, PLEDGED, TRANSFERRED OR ASSIGNED EXCEPT IN
         A TRANSACTION WHICH IS EXEMPT UNDER THE PROVISIONS OF THE 1933 ACT OR
         ANY APPLICABLE STATE SECURITIES LAWS, OR PURSUANT TO AN EFFECTIVE
         REGISTRATION STATEMENT OR IN A TRANSACTION OTHERWISE IN COMPLIANCE WITH
         APPLICABLE FEDERAL AND STATE SECURITIES LAWS.

         THE SALE, PLEDGE, TRANSFER, ASSIGNMENT OR OTHER DISPOSITION OF THE
         SHARES REPRESENTED BY THIS CERTIFICATE IS RESTRICTED BY AND SUBJECT TO
         THE PROVISIONS OF A PURCHASE AGREEMENT DATED AS OF SEPTEMBER 2, 2003, A
         COPY OF WHICH IS AVAILABLE UPON REQUEST FOR INSPECTION AT THE OFFICE'S
         OF THE COMPANY. ANY SUCH REQUEST SHOULD BE ADDRESSED TO THE SECRETARY
         OF THE COMPANY.

                  9. SUCCESSORS AND ASSIGNS; NO THIRD PARTY BENEFICIARIES. This
Agreement shall bind and inure to the benefit of the Company and the Purchasers
and the respective successors, permitted assigns, heirs and personal
representatives of the Company and the Purchasers; PROVIDED that the Company may
not assign its rights or obligations under this Agreement to any Person without
the prior written consent of the Purchasers, and PROVIDED FURTHER that the
Purchasers may not assign their rights or obligations under this Agreement to
any Person (other than an Affiliate) without the prior written consent of the
Company. This Agreement is intended for the benefit of the parties hereto and
their respective permitted successors and assigns, and is not for the benefit
of, nor may any provision hereof be enforced by, any other person.

                  10. NOTICES. Each notice, demand, request, request for
approval, consent, approval, disapproval, designation or other communication
(each of the foregoing being referred to herein as a notice) required or desired
to be given or made under this Agreement shall be in writing (except as
otherwise provided in this Agreement), and shall be effective and deemed to have
been received (i) when delivered in person, (ii) when sent by fax with receipt
acknowledged, (iii) five days after having been mailed by certified or
registered United States mail, postage prepaid, return receipt requested, or
(iv) the next business day after having been sent by a nationally recognized
overnight mail or courier service, receipt requested. Notices shall be addressed
as set forth below:

         If to any of the Purchasers, at the address set forth under such
Purchaser's name on SCHEDULE A.

         If to the Company:

                  CommVault Systems, Inc.
                  2 Crescent Place
                  Oceanport, New Jersey 07757
                  Attn:  N. Robert Hammer
                  Facsimile:  (732) 870-4514

         With a copy to:

                                      -16-

<PAGE>

                  Mayer, Brown, Rowe & Maw LLP
                  190 S. LaSalle Street
                  Chicago, Illinois 60603
                  Attention: Philip J. Niehoff
                  Facsimile: (312) 701-7711

                  11. FURTHER ASSURANCES. At any time or from time to time after
the Closing, the Company, on the one hand, and the Purchasers, on the other
hand, agree to cooperate with each other, and at the request of the other party,
to execute and deliver any further instruments or documents and to take all such
further action as the other party may reasonably request in order to evidence or
effectuate the consummation of the transactions contemplated hereby and to
otherwise carry out the intent of the parties hereunder.

                  12. PUBLIC DISCLOSURE. Except as required by Law or the rules
of any stock exchange (in which case the Company shall give Putnam notice at
least 24 hours prior to any public announcement containing its name), no public
announcement or other publicity regarding the transactions referred to herein
shall be made by any of the Purchasers or the Company or any of their respective
Affiliates, officers, directors, employees, representatives or agents, without
the prior written agreement of the Purchasers and Company, in any case, as to
form, content, timing and manner of distribution or publication; PROVIDED,
HOWEVER, that nothing in this Section shall prevent such parties from (i)
discussing such transactions with those Persons whose approval, agreement or
opinion, as the case may be, is required for consummation or subsequent review
of such particular transaction or transactions or (ii) disclosing such
information about such transactions in a registration statement or prospectus in
connection with the Initial Public Offering or (iii) if the disclosing party is
a Purchaser, disclosing such Purchaser's investment herein provided that such
disclosure does not mention any other Purchaser by name and is approved by the
Company in writing. Each of the parties acknowledge and agree that there would
be no adequate remedy at Law if it fails to perform its obligations under this
Section 12 and accordingly agrees that each of the other parties, in addition to
any other remedy to which it may be entitled at Law or in equity, shall be
entitled to compel specific performance of the obligations of the first party
under this Section 12.

                  13. WAIVER AND AMENDMENT. With the written consent of the
Company and the record holders of 66 2/3% of the Conversion Shares (including
the Conversion Shares represented by the Shares as if the Shares were converted
into Conversion Shares), (i) the obligations of the Company under this Agreement
and the rights of the holders of the Conversion Shares under this Agreement may
be waived (either generally or in a particular instance, either retroactively or
prospectively, and either for a specified period of time or indefinitely) or
(ii) this Agreement may be amended, changed, discharged or terminated.
Notwithstanding the foregoing, (x) if any waiver of any right or rights granted
to a Purchaser under this Agreement would uniquely affect such Purchaser, then
such waiver may be approved or granted by such Purchaser without the consent or
approval of any other Purchaser and (y) if any waiver or amendment of any right
or rights granted to a Purchaser under this Agreement would adversely affect
only a given Purchaser, then such amendment or waiver may not be effected
without the consent or approval of such affected Purchaser. Neither this
Agreement nor any provisions hereof may be amended, changed, waived, discharged
or terminated orally, but only by a signed statement in writing.

                                      -17-

<PAGE>

                  14. ENTIRE AGREEMENT. This Agreement and the Registration
Rights Agreement constitute the entire agreement, and supersede all other prior
agreements and understandings, both written and oral, among the parties hereto
and their affiliates with respect to the matters set forth herein.

                  15. SEVERABILITY. If any provision of this Agreement shall be
held invalid, illegal or unenforceable, the validity, legality or enforceability
of the other provisions hereof shall not be affected thereby, and there shall be
deemed substituted for the provision at issue a valid, legal and enforceable
provision as similar as possible to the provision at issue.

                  16. CAPTIONS. The Section references herein are for
convenience of reference only, do not constitute part of this Agreement and
shall not be deemed to limit or otherwise affect any of the provisions hereof.

                  17. COUNTERPARTS. This Agreement may be executed in one or
more counterparts, each of which shall be deemed an original but all of which
shall constitute one and the same instrument.

                  18. GOVERNING LAW. This Agreement shall be governed by, and
construed and enforced in accordance with, the laws of the State of Delaware.

                  19. WAIVER OF JURY TRIAL. THE COMPANY AND THE PURCHASERS
HEREBY WAIVE ANY RIGHT THEY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY
ACTION, PROCEEDING OR LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF, UNDER OR
IN CONNECTION WITH THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED THEREBY.

                  20. JOINT PARTICIPATION IN DRAFTING. Each party to this
Agreement has participated in the negotiation and drafting of this Agreement. As
such, the language used herein shall be deemed to be the language chosen by the
parties hereto to express their mutual intent, and no rule of strict
construction will be applied against any party to this Agreement.

                  21. MASSACHUSETTS BUSINESS TRUSTS. A copy of the Agreement and
Declaration of Trust of each Putnam fund or series investment company (each a
"FUND") that is a Massachusetts business trust is on file with the Secretary of
State of the Commonwealth of Massachusetts and notice is hereby given that this
Agreement is executed on behalf of the Trustees of the relevant Fund as Trustees
and not individually and that the obligations of this Agreement are not binding
upon any of the Trustees, officers or shareholders of the Fund individually but
are binding only upon the assets and property of such Fund.

                                     * * * *

                                      -18-

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed and delivered as of the day and year first written above.

                         COMMVAULT SYSTEMS, INC.

                         By: /S/ N. ROBERT HAMMER
                             ---------------------------------------------------
                         Name:
                             ---------------------------------------------------
                         Title:
                              --------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                         PUTNAM OTC AND EMERGING GROWTH FUND
                         By Putnam Investment Management, LLC

                         By: /S/ CHARLES A. RUYS DE PEREZ
                             ---------------------------------------------------
                         Name: Charles A. Ruys de Perez
                         Title: Managing Director

                         TH LEE, PUTNAM INVESTMENT TRUST -
                         TH LEE, PUTNAM EMERGING
                         OPPORTUNITIES PORTFOLIO
                         By TH Lee, Putnam Capital Management, LLC

                         By: /S/ CHARLES A. RUYS DE PEREZ
                             ---------------------------------------------------
                         Name: CHARLES A. RUYS DE PEREZ
                               -------------------------------------------------
                         Title: MANAGING DIRECTOR
                                ------------------------------------------------

                         PUTNAM DISCOVERY GROWTH FUND
                         By Putnam Investment Management, LLC

                         By: /S/ CHARLES A. RUYS DE PEREZ
                             ---------------------------------------------------
                         Name: Charles A. Ruys de Perez
                         Title: Managing Director

                         PUTNAM WORLD TRUST II - PUTNAM EMERGING INFORMATION
                         SCIENCES FUND
                         By The Putnam Advisory Company, LLC

                         By: /S/ CHARLES A. RUYS DE PEREZ
                             ---------------------------------------------------
                         Name: Charles A. Ruys de Perez
                         Title: Managing Director

                                                              PURCHASE AGREEMENT
<PAGE>

                         VAN WAGONER PRIVATE OPPORTUNITIES FUND, L.P.

                         By: /S/ GARRETT VAN WAGONER
                             ---------------------------------------------------
                         Name: GARRETT VAN WAGONER
                               -------------------------------------------------
                         Title: GENERAL PARTNER
                                ------------------------------------------------

                         VAN WAGONER CAPITAL PARTNERS, L.P.

                         By: /S/ GARRETT VAN WAGONER
                             ---------------------------------------------------
                         Name: GARRETT VAN WAGONER
                               -------------------------------------------------
                         Title: GENERAL PARTNER
                                ------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                         WHEATLEY PARTNERS III, L.P.
                         By: Wheatley Partners III LLC, its General Partner

                         By: /S/ BARRY RUBENSTEIN
                             ---------------------------------------------------
                         Name: BARRY RUBENSTEIN
                               -------------------------------------------------
                         Title: CEO
                                ------------------------------------------------

                         WHEATLEY ASSOCIATES III, L.P.
                         By: Wheatley Partners III LLC, its General Partner

                         By: /S/ BARRY RUBENSTEIN
                             ---------------------------------------------------
                         Name: BARRY RUBENSTEIN
                               -------------------------------------------------
                         Title: CEO
                                ------------------------------------------------

                         WHEATLEY FOREIGN PARTNERS III, L.P.
                         By: Wheatley Partners III LLC, its General Partner

                         By: /S/ BARRY RUBENSTEIN
                             ---------------------------------------------------
                         Name: BARRY RUBENSTEIN
                               -------------------------------------------------
                         Title: CEO
                                ------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                         DLJ CAPITAL CORPORATION

                         By: /S/ KEITH B. GEESLIN
                             ---------------------------------------------------
                         Name: Keith B. Geeslin
                         Title: Managing Director

                         SPROUT CAPITAL IX, L.P.
                         By: DLJ Capital Corporation
                         Its: Managing General Partner

                         By: /S/ KEITH B. GEESLIN
                             ---------------------------------------------------
                         Name: Keith B. Geeslin
                         Its: Managing Director

                         SPROUT ENTREPRENEURS' FUND, L.P.
                         By: DLJ Capital Corporation
                         Its: Managing General Partner

                         By: /S/ KEITH B. GEESLIN
                             ---------------------------------------------------
                         Name: Keith B. Geeslin
                         Its: Managing Director

                         SPROUT IX PLAN INVESTORS, L.P.
                         By:  DLJ LBO Plans Management Corporation II
                         Its: General Partner

                         By: /S/ KEITH B. GEESLIN
                             ---------------------------------------------------
                         Name: Keith B. Geeslin
                         Its: Attorney in Fact

                                                              PURCHASE AGREEMENT
<PAGE>

                         /S/ THOMAS I. UNTERBERG
                         -------------------------------------------------------
                         THOMAS I. UNTERBERG

                         C.E. UNTERBERG, TOWBIN CAPITAL PARTNERS I, L.P.

                         By:  UTCM LLC
                         Its: General Partner

                         By: /S/ MARK G. HADLOCK
                             ---------------------------------------------------
                         Name: MARK G. HADLOCK
                               -------------------------------------------------
                         Title: SECRETARY OF UTCM, LLC
                                ------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                         CAMELOT CAPITAL L.P.

                         By: /S/ SCOTT M. SMITH
                             ---------------------------------------------------
                         Name: Scott M. Smith
                         Title: Managing Partner

                         CAMELOT CAPITAL II L.P.

                         By: /S/ SCOTT M. SMITH
                             ---------------------------------------------------
                         Name: Scott M. Smith
                         Title: Managing Partner

                         CAMELOT OFFSHORE FUND LIMITED

                         By: /S/ SCOTT M. SMITH
                             ---------------------------------------------------
                         Name: Scott M. Smith
                         Title: Managing Director

                                                              PURCHASE AGREEMENT
<PAGE>

                         AMERINDO INTERNET FUND PLC
                         BY: AMERINDO INVESTMENT INC.
                         ITS: MANAGER

                         By: /S/ GARY TANAKA
                             ---------------------------------------------------
                         Name: GARY TANAKA
                               -------------------------------------------------
                         Title: EXECUTIVE VICE PRESIDENT
                                ------------------------------------------------

                         /S/ K. FLYNN MCDONALD
                         -------------------------------------------------------
                         K. FLYNN MCDONALD

                         /S/ MICHAEL SANDIFER
                         -------------------------------------------------------
                         MICHAEL J. SANDIFER

                         /S/ MARC WEISS
                         -------------------------------------------------------
                         MARC WEISS

                                                              PURCHASE AGREEMENT
<PAGE>

                         AMAN VENTURES

                         By: /S/ WILLIAM J. BELL
                             ---------------------------------------------------
                         Name: WILLIAM J. BELL
                               -------------------------------------------------
                         Title: MANAGING PARTNER
                                ------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                         HFI PRIVATE EQUITY LTD.

                         By: /S/ BARRY SHAILER             /S/ HARRY WILKIN
                             ---------------------------------------------------
                         Name:   BARRY SHAILER                 HARRY WILKIN
                             ---------------------------------------------------
                         Title:  DIRECTOR                      DIRECTOR
                             ---------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>

                         DRW VENTURE PARTNERS LP

                         By: RBC Dain Rauscher Corporation, its
                         General Partner

                         By:/S/ MARY ZIMMER
                            ----------------------------------------------------
                         Name: MARY ZIMMER
                               -------------------------------------------------
                         Title: DIRECTOR OF FINANCE AND ADMINISTRATION, RBC
                                CAPITAL MARKETS SERVICES
                                ------------------------------------------------

                                                              PURCHASE AGREEMENT
<PAGE>
                                   SCHEDULE A

                                   PURCHASERS

NAME AND ADDRESS OF PURCHASER                 NUMBER OF SHARES       PRICE
-----------------------------                 ----------------       -----
Putnam OTC and Emerging Growth Fund               239,540      $   749,999.74
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

TH Lee, Putnam Investment Trust                   319,387      $ 1,000,000.70
TH Lee, Putnam Emerging Opportunities Portfolio
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

Putnam Discovery Growth Fund                       79,847      $   250,000.96
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

Putnam World Trust II - Putnam Emerging
Information Sciences                              159,693      $   499,998.78
Fund
c/o Putnam Investment Management, LLC
Two Liberty Square
Boston, MA  02109

Van Wagoner Capital Opportunities Fund, L.P.      463,111      $ 1,450,000.54
c/o Van Wagoner Capital Management
435 Pacific Avenue Suite 400
San Francisco, CA 94133
Attn: Garrett Van Wagoner
Fax: (415) 835-5050

Van Wagoner Capital Partners, L.P.                 15,969      $    49,998.94
Address same as above

Wheatley Partners III, L.P.                       335,296      $ 1,049,811.78
80 Cuttermill Road, Suite 311
Great Neck, NY 11021
Fax No.

with a copy to:

                                                              PURCHASE AGREEMENT

                                      A-1

<PAGE>

NAME AND ADDRESS OF PURCHASER                 NUMBER OF SHARES       PRICE
-----------------------------                 ----------------       -----
825 Third Avenue, 32d Floor
New York, NY 10022
Attn: Lawrence Wagenberg
Wheatley Associates III                            69,958      $   219,038.50
Address same as above

Wheatley Foreign Partners III                      73,826      $   231,149.20
address same as above

DLJ Capital Corporation                             3,899      $    12,207.77
c/o Sprout Group
11 Madison Avenue, 26th Floor
New York, NY 10010

Sprout Capital IX, L.P.                           778,878      $ 5,569,667.01
Address and notice same as above

Sprout Entrepreneurs' Fund, L.P.                    7,011      $    21,951.44
Address and notice same as above

Sprout IX Plan Investors, L.P.                     82,149      $   257,208.52
Address and notice same as above

Thomas I. Unterberg                               447,143      $ 1,400,004.73
c/o C.E. Unterberg, Towbin
350 Madison Avenue
New York, NY 10017
Facsimile: 212-389-8808

C.E. Unterberg, Towbin Capital Partners I, L.P.   159,693      $   499,998.78
350 Madison Avenue
New York, NY 10017
Attn: Mark G. Hadlock
Facsimile: 212-389-8401

Camelot Capital L.P.                              220,383      $   690,019.17
3 Pickwick Plaza
Greenwich, CT 06830 (203) 863-7400
Attn: Scott M. Smith
203-863-7400

Camelot Capital II L.P.                            15,763      $    49,353.95
address same as above

                                                              PURCHASE AGREEMENT

                                      A-2

<PAGE>

NAME AND ADDRESS OF PURCHASER                 NUMBER OF SHARES       PRICE
-----------------------------                 ----------------       -----
Camelot Offshore Fund Limited                      83,241      $   260,627.57
address same as above

Amerindo Internet Fund PLC c/o                    148,132      $   463,801.29
Amerindo Investment Advisors Inc.
399 Park Avenue, 22d Floor
New York, NY 10022
Attn: David Mainzer
Fax: 212-308-6988

K. FLYNN MCDONALD                                   8,000      $    25,048.00
One Embarcadero Center, Suite 2300
San Francisco, CA  94111-3162
Telephone:  (415) 249-1535
Facsimile:  (415) 834-3582

MICHAEL J. SANDIFER                                 3,500      $    10,958.50
6016 Lee Highway
Warrenton, VA  20187
Telephone:  (540) 428-2790
Facsimile:  (540) 428-2791

MARC WEISS                                         32,000      $   100,192.00
c/o Amerindo Investment Advisors Inc.
399 Park Avenue, 22nd Floor
New York, NY  10022
Telephone:  (212) 418-2520
Facsimile:  (212) 935-6975

HFI Private Equity Ltd                             24,084      $    75,407.00
Jardine House 4th Floor
33-35 Reid Street
Hamilton IIM 12 Bermuda
Attention: Barry Shailer
Facsimile: 441-295-3011

Aman Ventures                                      15,838      $    49,588.78
1500 Owl Creek Ranch Road
Aspen, CO 81611
Attention:
Facsimile: 970-923-8855

                                                              PURCHASE AGREEMENT

                                      A-3

<PAGE>

NAME AND ADDRESS OF PURCHASER                 NUMBER OF SHARES       PRICE
-----------------------------                 ----------------       -----
DRW Venture Partners L.P.                           4,461      $    13,967.39
60 South 6th Street
Minneapolis, MN 55402
Attn: Mary Zimmer MS 54N2
Facsimile:  (612) 373-1610

TOTAL SERIES CC                                                $15,000,001.06

                                                              PURCHASE AGREEMENT

                                      A-4

<PAGE>

                                   SCHEDULE B

                                  SUBSIDIARIES

CommVault Systems (Canada) Inc., a Canadian corporation
CommVault Systems Mexico S de RL de CV, a Mexican company
CommVault Holding Company BV, a Netherlands company
CommVault Systems Netherlands BV, a Netherlands company

                                                              PURCHASE AGREEMENT

                                      B-1

<PAGE>

                                   SCHEDULE C

                  1. Employment Agreement, dated as of January 20, 1999 and
amended as of May 3, 2001, between the Company and N. Robert Hammer, under which
Mr. Hammer has received options to purchase 5,622,400 shares of common stock.

                  2.Corporate Change of Control Agreements, between the Company
and (i) Louis Miceli, (ii) Brian McAteer, (iii) Larry Cormier, (iv) Al Bunte;
(v) David West; (vi) Scott Mercer and (vii) William Beattie.

                  3. Stock Plan dated as of May 22, 1996, pursuant to which the
Company is authorized to issue options to purchase 15,950,000 shares of its
common stock of which 14,525,731 shares have been granted.

                  4. The Company entered into an agreement with Northern
Concepts Incorporated ("NCI"), dated as of May 2000 pursuant to which 285,000
shares of the Company's common stock was issued in consideration for the
acquisition of the business of NCI by the Company.

                  5. Preferred Stockholders have (i) conversion rights, pursuant
to the Amended Certificate, and (ii) preemptive rights pursuant to (a) the
Stockholders' Agreement; (b) the Series AA Purchase Agreement, (c) the Series BB
Purchase Agreement and (d) the Existing Series CC Purchase Agreement.

                  6. EMC holds a warrant to purchase up to 3,000,000 shares of
common stock at an exercise of $6.27 per share. To the extent that EMC exercises
the warrant, holders of the Series AA Preferred Stock, Series BB Preferred Stock
and the holders of existing CC preferred stock will be entitled to purchase
shares of Common Stock of the Company at a price of $6.26 pursuant to preemptive
rights granted to such holders under their respective preferred stock purchase
agreements. Assuming that EMC exercises its warrant in full, the maximum number
of shares of Common Stock that would be sold pursuant to such preemptive rights
would be approximately 750,000 shares.

                                                              PURCHASE AGREEMENT

                                      C-1

<PAGE>

                                   SCHEDULE D

                         CORPORATE COMPLIANCE AGREEMENT
              EMPLOYEE INVENTION, CONFIDENTIALITY, NON-COMPETITION,
                      NON-SOLICITATION AND ETHICS AGREEMENT

         THIS AGREEMENT is made between me, the undersigned, and CommVault
Systems, Inc. and on behalf of CommVault Systems, Inc. and its affiliated
companies as they exist from time to time (hereafter referred to collectively as
"CommVault"), and in consideration of my employment by CommVault and in
consideration for the compensation to be paid to me in connection with this
employment:

                  1. DUTIES. I shall render faithful and efficient services to
CommVault and perform exclusively for CommVault such duties as may be designated
by CommVault from time to time, which may include the functions of inventing,
discovering and developing new and novel devices, methods, and principles
relating to the business, research, and development of CommVault.

                  2. DISCLOSURE OF INVENTIONS. I shall promptly disclose to
CommVault in writing all inventions (including, but not limited to, new
contributions, concepts, ideas, developments, discoveries, processes, formulas,
methods, compositions, techniques, articles, machines, and improvements), all
original works of authorship and all related know-how ("Inventions"), whether or
not patentable, copyrightable or protectable as trade secrets, conceived or made
by me, alone or with others, during the period of my employment with CommVault
and, in the case of clauses (b) and (c) below, during the period of my
employment by CommVault and at any time after I cease to be employed by
CommVault for whatever reason, which (a) relate in any manner to the actual or
anticipated business, research, or development of CommVault, (b) are developed
using equipment, supplies, facilities, trade secret or confidential information
of CommVault, or (c) result from work performed by me or work supervised by me
for CommVault.

                  3. ASSIGNMENT OF INVENTIONS. I shall assign and do hereby
assign to CommVault my entire rights to each Invention described in SECTION 2
hereof. As requested by CommVault, I will take all steps reasonably necessary to
assist CommVault in obtaining and enforcing any patent, copyright, or other
protection which CommVault elects to obtain or enforce, in any country, for the
Inventions which I assign to CommVault. I will take no action to jeopardize
CommVault's ability to obtain or enforce its rights in such Inventions. My
obligation to assist CommVault in obtaining and enforcing patents, copyrights,
and other protections shall continue beyond the termination of my employment by
CommVault for whatever reason, but CommVault shall compensate me at a reasonable
rate after the termination of my employment for time actually spent at
CommVault's request providing such assistance. If CommVault is unable, after
reasonable effort, to secure my signature on any document needed to apply for,
prosecute, or enforce any patent, copyright, or other protection in relation to
an

                                                              PURCHASE AGREEMENT

                                      C-2

<PAGE>

Invention, whether because of my physical or mental incapacity or for any
other reason whatsoever, I hereby irrevocably designate and appoint CommVault
and its duly authorized officers and agents as my agent and attorney-in-fact, to
act for and in my behalf and stead to execute and file any such document and to
do all other lawfully permitted acts to further the prosecution and enforcement
of patents, copyrights, or similar protections with the same legal force and
effect as if executed by me.

                  4. COMMVAULT CONFIDENTIAL INFORMATION. Because of my
employment by CommVault, I will have access to and will learn techniques,
know-how, or other information of a confidential nature concerning CommVault's
experimental and development work, trade secrets, procedures, business matters
or affairs, including, but not limited to, information relating to inventions,
disclosures, processes, systems, methods, formulas, patents, patent
applications, machinery, materials, research activities and plans, grant
proposals, costs of production, contract forms, prices, business plans,
strategies, competitive strengths and weaknesses, volume of sales, promotional
methods, and lists of names or classes of customers, as well as information of a
confidential nature received from CommVault's customers, joint ventures,
collaborators, etc., and information developed solely or jointly by me, included
in connection with Inventions ("CommVault Confidential Information").
Information shall, for purposes of this Agreement, be considered to be
confidential if not known by the trade generally, even though such information
has been disclosed to one or more third parties pursuant to distribution
agreements, joint research agreements, other agreements or collaborations
entered into by CommVault.

                  5. PROTECTION OF COMMVAULT CONFIDENTIAL INFORMATION. I shall
at all times use my best efforts and exercise utmost diligence to protect and
guard CommVault Confidential Information. I will not use CommVault Confidential
Information for personal gain or for any purpose outside of my employment by
CommVault or disclose any such information to any person or entity either during
or subsequent to my employment, without CommVault's prior written consent,
except to such an extent as may be necessary in the ordinary course of
performing my duties as an employee of CommVault.

                  6. USE OF COMMVAULT CONFIDENTIAL INFORMATION. I shall not, for
my own account or as an officer, member, employee, consultant, representative,
or advisor of another, during my employment with CommVault or at any time
thereafter for any reason whatsoever, engage in or contribute my knowledge to
engineering, development, manufacture, research, business analysis or sales
relating to any product, equipment, process, or material that relates in any way
to the actual or anticipated business or research and development of CommVault,
without the written permission of CommVault. However, the foregoing provision
shall not prohibit me from engaging in any work at any time after leaving the
employ of CommVault, PROVIDED, that CommVault Confidential Information is not
involved in such work AND I am not in violation of any other term of this
Agreement or any other agreement entered into between me and CommVault. The
provisions of this SECTION 6 shall not be construed as limiting to any extent my
continuing obligations pursuant to the provisions in SECTION 5.

                                                              PURCHASE AGREEMENT

                                      C-3

<PAGE>

                  7. IMPROPER USE OR DISCLOSURE OF CONFIDENTIAL INFORMATION. I
shall not, during my employment with CommVault, or at any time thereafter,
improperly use or disclose any proprietary information or trade secrets of any
former or current employer or other person or entity and I will not possess or
bring onto the premises of CommVault any such proprietary information without
the prior written consent of such employer, person or entity.

                  8. OTHER RESTRICTIONS ON EMPLOYEE. I represent that there are
no other agreements or requirements to assign any invention or discovery
conceived or made by me, alone or with others, unless I have so indicated at the
end of this Agreement.

                  9. DISCLOSURE IF INVENTIONS. I represent that I have listed
and described in detail at the end of this Agreement all inventions, if any,
patented and unpatented, which I conceived or made PRIOR to my employment by
CommVault. Any invention not so listed and described shall be presumed to have
been made during my employment by CommVault.

                  10. RETURN OF COMMVAULT COMPANY INFORMATION. Upon termination
of my employment with CommVault for any reason, I shall disclose and provide to
CommVault all originals and all copies which are in my possession or under my
control, of all notes, memoranda, records, reports, drawings, blueprints, codes,
programs. Software, manuals, materials and data of any nature which are the
property of CommVault, which shall include, but not be limited to, every item in
my possession or under my control which contains any CommVault Confidential
Information.

                  11. NON-COMPETITION AND NON-SOLICITATION. I acknowledge that
because my knowledge of the CommVault Confidential Information and the personal
contacts with the customers and employees of CommVault acquired by me during my
employment, CommVault would be irreparably damaged should I, in any manner or
form, enter into any form of competition with CommVault. I, therefore agree that
at all times during my employment and for a period of TWELVE (12) MONTHS
thereafter, I will not directly or indirectly, in any individual or
representative capacity, carry on, engage or participate in any business that is
in competition in any manner whatsoever with the business of CommVault, except
as expressly provided for in this Agreement, or as may hereafter be expressly
agreed to in writing by CommVault. Further, I agree to not directly or
indirectly hire, seek to hire, or refer for other employment any current
employee of CommVault nor will I, in any manner or capacity, directly or
indirectly: divert or attempt to divert from CommVault, through any means
whatsoever, any business or customers of CommVault, during the TWELVE (12) MONTH
period following my termination of employment. The phrase "carry on, engage or
participate in any business that is in competition in any manner whatsoever with
the business of CommVault" shall include, but not be limited to, the doing by
you or by any person, firm, corporation, association or other entity that
directly or indirectly, through one or more intermediaries, is controlled by, or
is under common control with, or controls you, of any of the following acts
other than as related to your services to CommVault pursuant to your employment
with CommVault: carrying on, engaging in or participating in any such business
as a principal, for your own account or solely, or jointly with others as a

                                                              PURCHASE AGREEMENT

                                      C-4

<PAGE>

partner (general or limited), joint venturer, shareholder or holder of any
equity security of any other corporation or entity, or as a consultant,
contractor, or subcontractor or agent of or for any person, firm, corporation,
association, or other entity or through any agency or by any other means
whatsoever; or utilizing for your own benefit, or making available to any
person, firm, corporation, association or other entity, any confidential or
proprietary proposals, financial statements, governmental filings, cost data,
business plans or correspondence relating to such information, or other
CommVault Confidential Information. I acknowledge and agree that, in light of
the nature of the business of CommVault, the foregoing activity and time period
restrictions are reasonable and properly required for the adequate protection of
CommVault, and that, in the event any such activity or time period restriction
is deemed to be unreasonable or unenforceable by a court of competent
jurisdiction, then I agree to submit to the reduction of such activity or time
period restriction to the extent necessary to enable the court to enforce such
restrictions to the fullest extent permitted under applicable law. It is the
desire and intent of the parties that the provisions of this Agreement shall be
enforced to the fullest extent permissible under the laws and public policies
applied by any jurisdiction where enforcement is sought.

                  12. ETHICS. I understand and agree at all times to: (a) follow
the policies and guidelines of CommVault, as set forth by CommVault from time to
time; (b) represent CommVault in a professional manner exhibiting appropriate
behavior consistent with the highest ethical standards; (c) not make any
disparaging comment or statement (written or oral) about CommVault; (d) comply
with all applicable federal, state, and local laws, ordinances, regulations and
codes, including all Security and Exchange Commission laws and regulations; and,
(e) to apply for national security or other governmental clearance, if requested
by CommVault.

                  13. GENERAL

         (a) I understand and agree that the restrictions of this Agreement are
limited only to those restrictions necessary for the adequate and legitimate
protection of CommVault. Each paragraph and subparagraph of this document is
separate from each other and constitutes a separate and distinctive covenant. In
the event any limitation hereunder is deemed to be unreasonable by a court of
competent jurisdiction, then I agree to submit to the reduction of such
limitation as the court shall deem reasonable. In the event that I am in
violation of any limitation herein, then the time limitation shall be extended
for a period of time equal to the period of time during which such breach should
occur.

         (b) I understand that nothing in this Agreement shall confer upon me
any right to continue in the employ of CommVault. I understand that the
restrictions contained in this Agreement shall survive the termination of my
employment with CommVault for any reason.

         (c) I certify that I have not entered into, and I agree to not enter
into any agreement, either written or oral, in conflict with this Agreement.

                                                              PURCHASE AGREEMENT

                                      C-5

<PAGE>

         (d) I hereby authorize CommVault to notify others, including, without
limitation, customers of CommVault and my future employers, of the terms of this
Agreement and my responsibilities hereunder.

         (e) This Agreement shall be governed by the laws of the State of New
Jersey, without regard to New Jersey choice of law principles, and adjudicated
in the courts located in the State of New Jersey. Each paragraph and
subparagraph shall be independent and separable from all other paragraphs and
subparagraphs, and the invalidity of a paragraph and subparagraph shall not
affect the enforceability of any of the other paragraphs and subparagraphs. For
purposes of this Agreement, the business of CommVault shall include the business
of any corporation, firm, or partnership, directly or indirectly, controlled by,
controlling, or under common control with CommVault or any partner or joint
venturer of CommVault. For any violation of this Agreement, a restraining order
and/or an injunction may be issued against me in addition to any other rights
CommVault may have under applicable law. In the event any party to this
Agreement is successful in any suit or proceeding brought or instituted with
respect to this Agreement or to enforce the Agreement, the prevailing party will
be paid by the losing party, in addition to other costs and damages, reasonable
attorney's fees and costs.

         (f) This Agreement shall be effective during the period of my
employment by CommVault and for any periods thereafter as set forth herein,
inure to the benefit of any successor or assignee of CommVault, and be binding
upon my heirs, administrators, and representatives.

I acknowledge that I am entering into this Agreement knowingly and voluntarily,
and that I have had an opportunity to review it with counsel of my choosing.

------------------------------------
Employee Signature

Dated:
      ------------------------------

USE THE SPACE BELOW AND THE BACK OF THIS AGREEMENT (IF NECESSARY) TO LIST ANY
AND ALL INVENTIONS CONCEIVED OR MADE BY ME PRIOR TO MY EMPLOYMENT WITH
COMMVAULT, AND A DETAILED DESCRIPTION THEREOF, AND OTHER AGREEMENTS OR
REQUIREMENTS TO ASSIGN INVENTIONS OR DISCOVERIES, AS DESCRIBED IN SECTIONS 8 AND
9 ABOVE.

                                                              PURCHASE AGREEMENT

                                      C-6

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