Environmental Scan of Distributed Digital Preservation Services:
A Collective Case StudyNathan Hall

M. Boock

Virginia Tech
560 Drillfield Drive
Blacksburg, VA 24060
1-540-553-2845
nfhall@vt.edu

Oregon State University
121 The Valley Library
Corvallis, OR 97331
1-541-737-9155
michael.boock@oregonstate.edu

ABSTRACTThis paper uses a collective case study to reveal similarities anddifferences in the operations and service models of nine
distributed digital preservation services. The study uncovers awide range of organizations and technical variations among thenine services, but finds that they can be grouped into three basic
service models.

KEYWORDS
Digital preservation service models, digital libraries, digital
curation, case study

1

INTRODUCTION

During the 2016 Annual Steering Committee Meeting of the
MetaArchive Cooperative, the Steering Committee initiated anenvironmental scan of services provided by comparable digitalpreservation consortia and vendors. This study is a high-level
overview of digital preservation service models, and includes an
exploration of organizational aspects such as governance, support
and training, documentation, community facilitation, outreach andcommunication, marketing, and membership; as well as technicalaspects such as functionality, setup and configuration, content,
ingest, storage, security, access, and integration; and finally,
compliance with selected National Digital Stewardship Alliance
Levels of Preservation[1].
Digital formats are highly sensitive to obsolescence, corruption,and degradation, elevating the importance of strategies andinfrastructure for preserving digital records. Successful digitalpreservation “combines policies, strategies and actions” that
ensure digital content survives in a usable form with an
overarching goal to safeguard public records, scientific advances,and cultural heritage[2]. Many libraries engaged in digitalpreservation are “increasingly committing to the use of largescale, comprehensive, distributed digital preservation systems”[3][4]. Such systems help libraries preserve greater amounts ofdata efficiently and cost-effectively according to standards andbest practices.
A number of programs and providers offer similar digitalpreservation services, many of which are backed by the same third

party vendors. However, they differ in their organizationalmodels, strategies, and sometimes, architectures. The increasing
number of options allows libraries to choose among several
categories of service provider. Libraries might make financial andtechnical commitments based on the stated values of their service
providers and peers within their community, how rigorously aservice provider follows established standards, or based on thecost of the service and how it fits in the library’s budget andstrategic plan. While we did not undertake a cost comparison
since that information would be proprietary and/or negotiable, thisstudy compares organizational and technical aspects of large-scale
digital preservation services so that libraries can be better
informed when deciding which providers make the most sense for
them.

2

METHODS

Through documentary analysis, surveys, and interviews[5], we
reviewed operations and service models of nine (MetaArchive,
APTrust, DPN, TDL, DuraCloud, Preservica, Chronopolis,
Rosetta, and Arkivum) distributed digital preservation service
providers. We analyze governance, organizational structure,
support and training, documentation, community facilitation,outreach and communication, marketing, membership,compliance with NDSA Levels of Preservation, functionality,
setup and configuration, content, ingest, storage, security, access,and integration. We conducted a collective study[6] because these
programs provide comparable functions yet have different
organizational models and our purpose is to “reveal the propertiesof the class” of programs[7]. This analysis is a collective casestudy because it is an exploration of multiple programs in order toinvestigate distributed digital preservation services[8]. Schultz
and Skinner[9] conducted a similar study that compared
underlying technologies for three distributed digital preservation
systems: Chronopolis, University of North Texas, andMetaArchive.
We created a rubric to compare each program across thecategories listed above. Some of the information to complete thisrubric comes from the organizations’ websites, and we received
additional information through personal communication withexecutive directors or other program officials. Because we spokewith the representatives of these organizations about facts about
their respective organizations, rather than opinions, Virginia

Tech’s Institutional Review Board waived the review
requirement. We compared the profiles of the nine service
providers and analyzed similarities and differences within thesample along the lines delineated by the question categories. The
themes and the comparative analysis together describe how thenine programs differ in their approach to managing digitalpreservation services.

board which includes investors and senior management, but does
not have a formal user group.
Table 1-Member Community[12] demonstrates opportunities
for community engagement associated with each preservation
service. Community discussion are monthly calls or online
forums. In-person gatherings are annual or bi-annual meetings.
Mailing lists distribute service and product updates.

We identify several limitations to this study, some of which are
general to case study research[8][10][11]. Additionally, due to theinformal nature of the semi-structured interviews, someparticipants may have interpreted questions differently from eachother, or the follow-up questions may have gone in different
directions in each interview. As a result there is limited basis forcomparison in some categories. The third limitation is that this is afast-moving area and some of these programs are planning andinitiating new services at the time of writing. Some findings
therefore may be out of date by the time of publication.

3.1.2 Support and Training

3

RESULTSThis section organizes the findings into categories for comparing
similarities and differences among the program in the sample.

3.1

Organizational Aspects

3.1.1 GovernanceAll organizations in the sample provide their users with digitalpreservation services, but each one articulates its mission in
distinct ways. The mission statements published on their websites
each note the importance of collaboration or connections withother preservation and access systems. The Arkivum and
Preservica websites state the sectors they serve without focusing
on the content. Other providers stated that their purpose is toensure the longevity of cultural heritage digital content, but do notprovide business model details in their mission statements. DPN
and Preservica list types of digital resources they preserve while
Chronopolis and TDL discuss the mission of preserving digitalcontent more generally. APTrust, Chronopolis, and DuraCloudeach identify a values statement, and DPN indicate that they have
one in development. The other institutions in the sample do nothave a formal values statement.
There are three distinct organizational types with equal
distribution in the sample. 1) APTrust, TD, and Chronopolis areeach legally constituted as a part of a university. 2) Preservica,
Arkivum, and Rosetta are commercial services. 3) DPN,
DuraCloud, and MetaArchive are non-profit limited liability
companies. Leadership varies across the sample, although
MetaArchive, DuraSpace, DPN, APTrust, Preservica, and TDL
are governed by boards or steering committees. MetaArchive,
APTrust, DPN, and TDL all accomplish technical and nontechnical development work through committees. Rosetta andPreservica have active user groups that meet regularly online, andat regular meetings and conferences. Arkivum has an executive

Most of the services provide training (see Table 2-Member
Support and Training[13]) in the form of new customer
orientations, instructional webinars, workshops, and/or video
tutorials. DPN identifies itself as more of a catalyst organization
instead of an educational organization, so they partner with otherprograms such as APTrust and DuraSpace for user support, andwith AVPreserve and Educopia for curriculum development.
TDL, APTrust, Arkivum, and MetaArchive provide in-person
orientation and training either remotely or on site. Arkivum,
Preservica, TDL, DuraCloud, and MetaArchive all offer training
via webinars, and DPN plans to offer them in the future. APTrustand TDL both provide informal in-person workshops on-site to
new members, whereas MetaArchive and DuraCloud offer inperson workshops on an irregular, ad hoc basis. Preservica
provides briefings and workshops targeted at specific users and atconferences. DuraCloud, Preservica, Arkivum, TDL, and Rosetta
all offer video tutorials through YouTube or Adobe Connect.
APTrust also has training videos on YouTube but notes that they
are slightly dated. All services offer support and troubleshooting
via email, phone, or both. DPN offers informal support with legal
agreements in digital preservation, but relies on APTrust and
DuraSpace for formal technical support for members.

3.1.3 Documentation
The availability of comparable documentation in the form ofFrequently Asked Questions and technical specifications varies
among the nine providers. Rosetta, TDL, DPN, DuraCloud and
APTrust, and to some extent MetaArchive have open technicaldocumentation. Chronopolis, Arkivum, and Preservica on theother hand do not make their technical documentation openly
accessible but it is available to customers. Among the threevendors, only Rosetta makes its documentation available to nonsubscribers, including their AIP data model, system integration
models, and user guides. DuraCloud and APTrust provide
technical information on an openly available wiki (DuraCloud) or
web site (APTrust) that includes knowledge bases of common
issues, release notes, and detailed information on features andservices. DPN provides an FAQ with documentation and code on
their openly available GitHub. In lieu of a knowledge base,Arkivum has an online collection of case studies and white
papers. Preservica, Chronopolis, and TDL do not have an open
knowledge base. TDL had one in the past and may develop
another one. MetaArchive provides technical specifications for
hardware on its website, but in-depth technical resources and aknowledge base are currently restricted to users.

3.1.4 Community Facilitation
Nearly all of the providers we spoke with have a community, user,or customer-focused staff position. This position is responsible forcommunicating with users about services, and for facilitating
community relations, meetings, and events. All except
Chronopolis and Arkivum provide mechanisms for community
discussion and product updates, either via mailing lists, Google
Groups, or subscriber user forums. Each organization in thesample has a program in place for facilitating conversations withand between users. MetaArchive hosts regular monthly
community calls that provide an opportunity for regularcommunication between community members. DuraSpace
publishes a quarterly newsletter that includes updates about
DuraCloud and ArchivesDirect. MetaArchive, Rosetta, DPN,
DuraSpace, and TDL hold annual user meetings. APTrust
members meet twice per year. Preservica facilitates user groupmeetings at conferences, and Rosetta, in addition to hosting anannual user group meeting, hosts quarterly working group web
meetings and meets with advisory groups as needed.

3.1.5 Outreach and Communication
Table 3-Outreach and Marketing[14] illustrates that all of the
programs engage with their community via social media. Most use
Twitter, but some also use LinkedIn, YouTube, or Facebook. The
commercial providers and DPN also sponsor conferences, andexhibits as well as join their non-profit and academic colleagues
as conference presenters and panelists. Arkivum attends sectorbased conferences in medicine and other fields.

3.1.6 Marketing
Preservica, Arkivum, and Rosetta engage in marketing, though
MetaArchive, TDL, and APTrust do not. DPN has publishedflyers and co-sponsored events such as PASIG and Digital
Preservation 2016. DuraCloud has exhibited at conferences, butdoes not engage in marketing. Chronopolis is developing
promotional materials, but has never exhibited at a conference.

3.1.7 Membership
There are slight variations in membership models andcomposition. MetaArchive has twenty-two members and oversixty participating institutions including consortia, academic
libraries, public libraries, archives, and museums. Nearly two
hundred institutions use DuraCloud, including cultural heritageand commercial enterprise users. DPN has over fifty members,
including universities, consortia, and one commercial entity(Figshare). DPN anticipates future membership to include public
libraries and cultural heritage institutions. APTrust has sixteen
members, all of which are ARL member academic libraries, but isexpanding membership to include public libraries and liberal arts
colleges. Chronopolis is not a membership organization, but the
replication nodes are at University of California at San Diego,
National Center for Atmospheric Research, and the University of
Maryland Institute for Advanced Computer Studies, and mostusers are at those institutions. TDL has twenty-two members

drawn from higher education institutions, though they considering
expanding their membership model. Arkivum serves
approximately one hundred institutions, though some share a
consortium account.

3.2 Technical Aspects
3.2.1 Setup and Configuration
MetaArchive members that host a storage server node follow
specifications, instructions, and support to set up a server toconnect to the MetaArchive network. Preservica provides a hosted
Cloud Edition that requires no installation, as well as an
Enterprise Edition that requires a local server and storage (e.g.
Windows or Linux servers with Network Attached Storage) and a
MySQL database for managing metadata. DuraCloud users set up
an account and then utilize a web dashboard to manually ingest
content, or they can install a DuraCloud Sync tool to automate
content ingest. Chronopolis and TDL both use SSH or DuraCloud.
APTrust uses an API. Arkivum sends hardware for the customer
to install, and then Arkivum runs the software installation andconfiguration.

3.2.2 Content
Table 4-Content and Ingest[15] demonstrates that all programsin the sample are format agnostic in that they support all fileformats,
content
types,
metadata
schemas,andstructures. Furthermore, they all support large file sizes as well as
BagIt bags. All of the services except for MetaArchive and
ExLibris have a drag-and-drop ingest interface, though ExLibris
and MetaArchive do have a simple graphic user interface for
uploading files through a web browser.

3.2.3 Ingest
There is wide variability in ingest methods within the sample.
MetaArchive has two ingest processes--one for public, live, webbased content, which is crawled and ingested via LOCKSS[16]plugins setup with parameters to automatically ingest repository
content, and another for non-public content that members place ona web server with simple directory listings. APTrust partners bag
their own content using the LOC BagIt specification, and thensubmit their bags through the APTrust API. Partners can track the
bag’s progress through final ingest into AWS. DuraCloud users
can add content manually via drag-and-drop to a web dashboard,or they can automate ingest through the DuraCloud Sync Tool.
DPN, Chronopolis, and TDL also use DuraCloud software to
upload content. TDL users can also use a desktop client that syncs
to the network from a folder, or they can use a command line
method that pushes from a server to DuraCloud. Preservica users
can upload content via a web dashboard, a local SIP creator, anetworked transfer agent, or Preservica’s Cloud Edition Bulk
Upload Service. Arkivum customers move files onto a networked
file share. Customers who use Arkivum’s Perpetua product canalso use AWS for ingest.

3.2.3 StorageAs indicated in Table 5-Storage[17] there is wide variation in
how different services handle storage. MetaArchive creates sevencopies at node sites. DuraCloud has multiple subscription plansthat offer two-to-four copies on separate cloud storage providers.
Preservica’s Cloud Edition includes one copy in S3 or Glacier,while their Enterprise Edition includes options for local storage
along with S3, Glacier, or Azure. DPN, Chronopolis, andArkivum each use a three-copy model, though one of Arkivum’s
copies is stored in a secure offline environment by a contracted
third-party vendor. APTrust’s model has six copies. TDL uses S3and Glacier, which together create copies at two locations.
Nearly all of the programs operate as hosted services so thatmembers do not need to install, run, or maintain servers or otherinfrastructure. Three of the services (DuraCloud, APTrust, TDL)
offer replication through Amazon Web Services Glacier and
S3. Preservica and Arkivum both offer managed hosted services,
as well as enterprise versions that run on local infrastructure.
MetaArchive, as a cooperative, has unique requirements for its
members, who must purchase and host servers to run LOCKSS
software and replicate other members’ content. This configuration
reduces MetaArchive’s membership fee by transferring IT costs tomember staff time and hardware. Alternatively, members can pay
a hosted storage service fee.
All services in the sample provide regular fixity checking.
Arkivum has the most frequent intervals with monthly checks.
TDL reported biannual checks. Most participants did not reportfixity check frequency.

3.2.4 Security
DPN security is managed by contributing partners. APTrust uses
data integrity and siloing through AWS to secure its data. APTrust
has scheduled a security audit for the coming year. Preservica did
not provide details about security beyond access roles and rights.
All users must authenticate with a username and password, andeach user account is set up with a series of roles which allowing
users to see content based on their defined roles. These
configurations can be as granular as file level permissions.
Arkivum data uses file encryption and customer-supplied
encryption keys. TDL and DuraCloud’s content security employs
cloud storage service provider protocols (e.g. Amazon,
RackSpace). All DuraCloud content uses https for encryption and
TDL uses SSH and requires login and access control settings.
MetaArchive member server cache communications are SSL
encrypted. The setup of MetaArchive server caches includes
firewall and port settings to restrict access only to other network
servers.

3.2.5 Access
Preservica, Arkivum, APTrust, Chronopolis, DuraCloud, andTDL all restrict access through authenticated user
credentials. MetaArchive’s access system differs in that eachmember institution is a storage node and provides its own serverwhich is managed by a local systems administrator. Each node

hosts a copy of data from other institutions on the network, but
only designated system administrators have user accounts formember server caches. No member is permitted to access anothermember’s stored collections. Login pages are only accessible tothe host member institution and the MetaArchive central staff, and
SSH is required for remote access.
Each preservation system has a separate method for restoring
content. MetaArchive members submit a request to MetaArchive
central staff who establish a secure connection to the nodes withcopies of the requested content, and then the software constructs
an uncompressed ZIP package and makes it available for themember to download. DuraCloud users utilize a retrieval tool to
download content to a local environment. Arkivum customers
copy files back out through a fileshare, or if the customers use
Archivematica, they can download ingest packages from thatinterface. Preservica’s Universal Access module allows users tosearch, find, and download publicly available content, thoughdetails are not available for bulk download and restoration
processes. Preservica has many different levels of accessibility
that can be implemented, in addition to user-defined restrictions.
APTrust members restore content through the API, and TDL
members use the DuraCloud interface, but TDL staff retrieve
content from S3 and Glacier.

3.2.6 Integration
DuraCloud integrates with and backs up DSpace, DSpace Direct,
Archive-It, Archivematica, DPN, and Chronopolis. Through the
REST API, DuraCloud allows integration in Ruby and Java.
Preservica supports automated workflows to bulk ingest exported
DSpace, PastPerfect, and CONTENTdm data, as well as bulk
ingest of SharePoint, Outlook and Gmail packages, and website
harvesting data. Preservica also supports integration with catalog
systems including ArchivesSpace, Axiell, CALM, and AdLib fordata management. APTrust’s PREMIS logs and API for bag
ingest allow integration with any system. Arkivum integrates with
CRIS, EPrints, DSpace, Pure, Archivematica, and Figshare.
Chronopolis integrates with Archivematica via DuraCloud and
DPN. MetaArchive integrates with DSpace via the LOCKSS
plugin, or through the DSpace replication task suite.

4

CONCLUSIONS

4.1 TechnicalThree main service models emerge in this study. Most of theservices follow a consistent hosted service model. APTrust,
Chronopolis, and TDL are all legally constituted within public
universities and use third-party applications such as DuraCloudsoftware or Amazon Web Services Glacier and S3. MetaArchiveis unique in its distributed network of nodes, where eachmember/partner provides its own storage hardware andcontributes more staff time. In this regard, MetaArchive operates
more like a cooperative. DPN is different because it operates as anindependent umbrella organization that links other programs
together, adding further replication and geographic distribution.

4.2 Organizational
Prior to data collection we anticipated seeing significant
differences between commercial and non-commercial providers,
and these differences did manifest in organization and mission—some providers are privately held commercial firms and otherproviders have a non-profit model. The non-profit providers
are either legally constituted within public universities or as
independent LLCs. While mission statements and business models
articulated by the commercial entities exhibit competitive
business services around data preservation, the non-profit
organizations used language expressing a direct interest in
sustainability of the content itself for posterity’s sake.
Several of the services in the sample expressed plans or an interestin expanding their services to public libraries. This expansion isgood news for the preservation of cultural heritage materials anddata in public libraries. Among the sample the opportunity to
expand services to this population will create new opportunities
and challenges in coming years.

4.3 GeographicalAll of the surveyed programs except Arkivum are based in the
United States. Arkivum and all of its data are stored in the UKbased data centers. Understandably, the scale of size and distanceare different in the U.S. and U.K. so Arkivum’s nodes are a few
hundred miles apart as opposed to a thousand miles or more, as is
the case with some storage nodes and third-party data centers in
the U.S. In spite of this difference, Arkivum’s data centers are still
far enough apart to have different disaster threats. Furthermore,
Arkivum is the only service in the sample that offers offline
secure storage in its preservation model.
While we are not aware of recent studies that parallel the scope of
this one, it is a fertile area for further research. Some participantsin this study are preparing to announce new services at the time ofwriting so a follow up study would yield different findings.
Additionally, a larger and more diverse sample would be useful.
Eight of the nine participants are U.S.-based, and one is based in
the U.K. We became aware of other service providers that wewould include in a follow-up, yet even these are exclusively
within English-speaking countries. Aside from the scope, a few
other subjects warrant further investigation. An analysis of costversus effort could serve institutions investing in distributed
digital preservation. Spalenka[18] writes that administrators ordigital preservation program managers “should not assume that an
application bundling many digital curation and preservation
functions together with a single user interface will necessarily
provide an entirely comprehensive and worry-free experience”
because some service providers assume that users have alreadyaddressed the basic preservation needs. A tool that identifies
existing resources and gaps in digital preservation architecture andmatches that assessment with digital preservation services thatbest address the gaps would be a useful application of thesefindings.

Hopefully this study assists decision makers identify the best
digital preservation service providers for their organization, andexpands our participants’ understanding of the digital preservation
service environment while also helping them identify strengths,
weaknesses, opportunities, and threats of their respective
programs and service models.

ACKNOWLEDGMENTS
We would like to thank Carly Dearborn (Purdue University), Sam
Meister (MetaArchive), Mary Molinaro (DPN), Bradley Daigle(APTrust), Kristi Park and Ryan Steans (TDL), David Portman
and Tom Hodge (Preservica), Sibyl Schaefer (Chronopolis),
Matthew Addis (Arkivum), and Heather Greer Klein and Bill
Bannon (DuraCloud) for their time, contributions, andcooperation in this study.

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