License Server Redundancy
UNDERSTANDING THE BARTENDER®
AUTOMATIC FAILOVER SOLUTIONSUPPORTS: BARTENDER ® 2021 PREVIEW 2ContentsOverview
Comparing the Triad and Backup Server Relationships
Triad Relationship
Server Roles and Synchronization
Creating and Managing the Triad Relationship
Requirements
Notes
Backup RelationshipSample Scenario
Creating and Managing the Backup Relationship
Requirements
Notes
Related Documentation

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Overview
License server redundancy provides an automatic failover solution to keep your print production
environment running seamlessly in the event that one license server fails.
When BarTender is installed, you can use Administration Console to configure redundancy by setting
up license servers in a backup relationship that uses two servers or in a triad relationship that uses
three. Then, if the main or primary server cannot be reached by a BarTender client computer for any
reason, the client automatically connects instead to the other servers in the relationship.

Comparing the Triad and Backup Server Relationships
Understanding the differences between the triad and backup server relationship will help you
determine which configuration is the best choice for your organization.

Triad Relationships
A triad server relationship generally requires less management effort after setup is complete,
but the following points should be considered before you configure this relationship:lllA triad relationship requires three servers, but these three serves behave like a single server
and require only one license.
Only Enterprise edition licenses can be used for triad relationships.
If network connectivity among servers is not reliable, using a triad server configuration can beproblematic. When connectivity between the servers is not reliable, the need to satisfy
quorum becomes a factor of failure. Though the triad relationship has implemented tolerable
timeouts and connection retries between triad servers, if the connection is broken repeatedly
for several minutes or longer, the triad will fail. If your network connections are subject tothese types of interruptions, a backup server relationship is the preferred choice.

Backup Relationships
A backup server relationship can be more flexible and have fewer restrictions than a triad
relationship, but the following points should be considered before you configure this relationship:llll

A backup relationship requires only two servers, and each server is fully operational when themachines cannot see one another, but each server requires its own license.
Both servers in a backup relationship can host non-Enterprise edition licenses, but there mustbe at least one mapped license, which does require an Enterprise edition license.
A backup relationship doesn't require a network connection between the main server and thebackup server. However, extra care is required to make sure the server settings aresynchronized so that failover will occur as expected. If network connection is available, server
settings are synchronized automatically. If network connection is not available, users can still
export settings from the main server and import them to the backup server to make sure thesettings are synchronized.
The servers in the backup relationship accept requests independently. BarTender clients canLicense Server Redundancy

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set their current licenses to any licenses on either servers. In normal operation, users can use
these two servers to share the loads. In the case of server crash, clients will failover to theother running server automatically, and when the server hosting the client’s current license isback online, the client automatically switches back to its original server.
lPrint usage statistics in the two servers are separate. They are not merged. So if a client fails
over to the other server, its printer usage statistics are scattered between the two servers.

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Triad Relationship
In a triad relationship, you configure three license servers to act as primary, secondary, and tertiary
servers. These servers host the same licenses and share the same settings, so they behave like asingle server. The servers maintain regular communications with each other to verify that at least
two of the three - a quorum - are running and communicating. BarTender clients automaticallyconnect to whichever server can process their requests.

Server Roles and Synchronization
When the primary server connects to either the secondary or tertiary server, it becomes the active
server and can then process BarTender client requests.
If the primary server fails for any reason and cannot connect to either the secondary or tertiary
server, it reports to the BarTender clients that the secondary server is now the active server (if it cando so) and then stops accepting client print requests. When this happens, the secondary server tries
to connect to the tertiary server to confirm that the tertiary also cannot connect to the primary. If theconnection and confirmation are made, the secondary server becomes the active server (andnotifies the tertiary server about the change) and can then process requests. The secondary server
periodically tries to contact the primary server, and if it succeeds, it transfers control back to theprimary.
The tertiary server's role is to satisfy quorum. Single servers in a triad do not act alone. If both theprimary and secondary servers become unavailable, the tertiary server does not process print
requests but monitors the other servers for availability.

Creating and Managing the Triad RelationshipTo create a triad relationship, click Setup Server Redundancy on the Redundancy page in
Administration Console to start the Redundancy Setup wizard. This wizard guides you through theprocess of naming the triad and selecting the servers that you want to use as the primary,secondary, and tertiary servers.

Viewing and Managing the Triad Relationship
After you create the triad relationship, it is displayed on the Redundancy page in Administration
Console as a diagram of the three servers that provides information about the servers (including
name, IP address, and port), the role and status of each server (including an indication of which
one is currently the active server), and the number of licenses that the triad includes.

License Server Redundancy

5You can manage the triad's settings, such as changing the role of a selected server or replacing aserver, by clicking to display a menu of management options.

Changing the Triad Roles
You might want to change the role of a server in a triad, such as redesignating the secondary tothe primary role. To do this, click , and then click Change Triad Roles to start the Change TriadRole wizard.

Replacing a Server
You might need to replace a server if it becomes damaged or unstable. You can do this without
having to dismiss the triad relationship, which means that your license settings do not need tobe changed, although a new triad relationship with the new server is created. To replace aserver, click , and then click Replace Triad Node to start the Replace a Triad Node wizard.

Dismissing the Triad RelationshipTo dismiss a triad relationship, click , and then click Dismiss This Triad to start the Dismiss
the Triad wizard. You can always dismiss a triad, even if one or more servers are disconnected. If

License Server Redundancy

6the servers continue to host licenses and if at least two servers are connected, the wizard
provides options for you to deactivate the licenses, move them to another server, or keep themin the triad's current active server.

Requirements
The following requirements must be met for the servers that you use when you configure a triadrelationship:l

You have permissions to administer all three servers as configured in the access control rules,
which are displayed under Server Access on the Licensing page in Administration Console.

l

The server is running BarTender 2021 or a later version.

l

At least one Enterprise edition license is installed and activated.

l

The server is not already part of a triad or backup redundancy relationship.

lThe server is not a provisional license server.

l

The server is a printer-based license server.

Noteslllll

A client computer that is running BarTender 2019 can connect to a triad server.
Triad redundancy can be created and managed only when the BarTender Suite is activatedwith an Enterprise license. However, regardless of the license edition, users can always
dismiss a triad if they have permissions to administer all three servers as configured in theaccess control rules, which are displayed under Server Access on the Licensing page in
Administration Console.
Only Enterprise edition licenses can be used for triad relationships.
Licenses that are activated for single-server use cannot work in a triad, and vice versa.
Therefore, license reactivation is required after a triad is created and after it is dismissed.
Licenses that are activated for a triad cannot work when one or more servers are replaced.
Therefore, license reactivation is required after a server is replaced.

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ll

Printer usage statistics for client computers are synchronized and merged automatically aftera failover occurrence, so you can track printer usage regardless of whether the primary or
secondary server was being used.
If you are configuring a triad relationship while the servers cannot contact the Seagull
Activation Server, the servers that you want to use must not be hosting licenses before you
create the triad. If there are licenses on the servers, you must deactivate them before you
create the triad and then reactivate them afterward.

License Server Redundancy

8Backup Relationship
In a backup relationship, you configure a main license server and a backup license server. Theseservers host different licenses, so you must map one or more licenses from the main server to thebackup server (redundancy takes effect only for mapped licenses). The servers share the samesettings, and when they are connected, settings are periodically synchronized between the main
server and the backup so that the backup can take over the responsibility of the main server whenneeded.
A backup relationship does not require connectivity between the two servers, however. Both servers
run independently. If one server becomes unavailable, the other takes over as long as the client cancommunicate with the other server. The consequence of having no connectivity between servers isthat any changes in their settings are not automatically synchronized.

Sample Scenario
The following sample scenario describes how the backup relationship provides automatic failover inthe event that the main server becomes unavailable:
In your print environment, you install BarTender and the BarTender Licensing Service on
three computers: Server A, Server B, and Client C. You create a backup relationshipbetween A (the main server) and B (the backup server) by mapping the licenses that A
hosts to the licenses that B hosts. You then activate the instance of BarTender that isinstalled on C (the client computer) by using a license that A hosts. When you do this,BarTender print requests that C sends are forwarded to A. If C cannot reach A for any
reason, those BarTender print requests are redirected to B.
The settings that are shared between A and B (including permissions, license partitions,printer pools, and so on) are continually synchronized as long as the two servers areconnected.
It is not required that client computers use the licenses that are hosted on the main server; theclient could use a license that the backup server hosts. In this case, the main server provides
redundancy for the backup server.

Creating and Managing the Backup RelationshipTo create a backup relationship, click Setup Server Redundancy on the Redundancy page in
Administration Console to start the Redundancy Setup wizard. This wizard guides you through theprocess of selecting the servers that you want to use as the main and backup servers and ofmapping the licenses from the main server to the backup server.
If you want to set up a backup relationship but are using a computer that cannot connect to both themain server and the backup server at the same time, follow these steps:
1. On a computer that is connected to the backup server, export a license list file. For
information about how to do this, refer to the procedure that follows under Exporting a
License List File.
2. On a computer that is connected to the main server, do the following:

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a. On the Redundancy page in Administration Console, click Setup Server Redundancy tostart the Redundancy Setup wizard to select and configure the main server.
b. On the Select the Backup Server page of the wizard, select Specify by previously
exported server license list, browse to the license list file that you created previously,and then click Next.
c. On the Map Licenses page, click Import Backup Server's License List. The licenses areimported and mapped. Click Next.
d. On the Export Backup Relationship Setup Data page, select the path to save the.bkdat file to, and then click Next. You will use this file to configure the backup
relationship on the backup server later.
3. On a computer that is connected to the backup server, do the following:a. On the Redundancy page in Administration Console, click Setup Server Redundancy tostart the Redundancy Setup wizard to select and configure the backup server.
b. On the Create a Backup Relationship page of the wizard, select I want to import abackup relationship data file, browse to the .bkdat file that you saved previously, andthen click Next.
c. Complete the rest of the wizard steps.

Exporting a License List File
You can export and save a license list file so that you do not have to manually enter product key
codes when you use the wizard to map licenses from the main server to the backup. To do this,follow these steps:
1. Start Administration Console on a computer that can connect to the server thatyou want.
2. In the left navigation pane, click Licensing to open the Licensing page.
3. Under License Servers, right-click the target server, and then click Export license
list.
4. In the Export License List dialog, click Export.
When you use the Backup Relationship Setup wizard to set up license mapping, you are given anoption to import this license list file.

Viewing and Managing the Backup Relationship
After you create the backup relationship, it is displayed on the Redundancy page in
Administration Console in a table that provides information about the servers (including name,IP address, and port) and the role and status of each server.

License Server Redundancy

10You can manage these servers by using the Backup Relationship Setup wizard. The wizard
evaluates the status of the relationship between the servers and automatically displays thepage that applies to the relationship. To access this wizard, use one of the following methods:llRight-click a relationship to display a menu that indicates the page in the Backup
Relationship Setup wizard that applies to the selected relationship (for example,
when Manage Backup Relationship and Export Main Server's Settings appears
in this list and you click this option, the wizard starts on that page).

Point to theicon to display the page in the Backup Relationship Setup wizard
that applies to the selected relationship. Click the icon to start the wizard on thatpage.

Dismissing the Backup RelationshipTo dismiss a backup relationship, right-click it, and then click Dismiss Backup Relationship.
Alternatively, click
to start the Backup Relationship Setup wizard on the Dismiss a Backup
Relationship page.

Requirements
The following requirements must be met for the servers that you use when you configure a backup
relationship:l

You have permissions to administer both the main and the backup server as configured in theaccess control rules, which are displayed under Server Access on the Licensing page in
Administration Console.

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The server is running BarTender 2021 or a later version.

l

At least one Enterprise edition license is installed and activated.

l

The server is not already part of a backup or triad redundancy relationship.

l

The server is not a provisional license server.

l

The server is a printer-based license server.

Notesllllll

A client computer that is running BarTender 2019 can connect to a server that is in a
BarTender 2021 backup relationship. However, if the main server becomes unavailable, theclient does not automatically connect to the backup server.
Licenses that are hosted on the main server can be mapped to licenses on the backup server
without regard to the number of printers that are associated with the licenses.
Both servers in a backup relationship can host licenses that are not mapped.
The BarTender client computer can use only as many printers as are allowed by the licensethat is hosted on the server that the client is currently connected to.
For load balancing purposes, you can configure half of your client computers to use the main
server's license and the other half to use the backup server's corresponding (mapped)
license. When both servers are running, the load is distributed over the two servers. If either
server is down, all clients send requests to the other running server.
Printer usage statistics for client computers are not merged after a failover occurrence. Themain and backup servers log printer usage statistics separately.

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Related Documentation
User Guides
lGetting Started with BarTender
https://support.seagullscientific.com/hc/categories/200267887

Other Resources
Please visit the BarTender website at https://www.seagullscientific.com.

Version 2020-08-20 Copyright © 2020 Seagull Scientific, Inc.