By configuring two or more Sun Ray servers in a failover group, you can reduce interruption of new service availability in the event that one server fails. If you plan to combine existing Sun Ray servers into a failover group, or to upgrade an existing failover group, please consider the following:
You should always upgrade the secondary servers first before upgrading the primary server. New functionality from the release may not work until all the servers in the failover group are upgraded.
Before you upgrade a given server, make sure that Sun Ray Client users terminate their sessions.
If upgrading servers in a large configuration at once is not convenient, upgrade one or two servers at a time until the entire configuration is complete.
For best results in groups of four or more servers, configure the primary server so that it serves only the Sun Ray data store. Configure the secondary servers so that they serve users directly in addition to serving the data store.
While upgrading the primary server, secondary servers will not be able to do any updates to the data store.
To take advantage of the new features in this release, do not mix different Sun Ray Software versions within a failover group. Failover groups that use more than one software version revert to the functionality of the earliest version.
Using the Admin GUI to restart or reset Sun Ray services does not work across servers with different Sun Ray releases. For example, even if you use the Admin GUI to restart all the servers in a failover group that are running the latest Sun Ray Software release, you should still restart or reset any Sun Ray servers running earlier versions of Sun Ray Software.
Turn off all firmware updates until all the servers in a failover group are upgraded. For details, see the How to Disable All Firmware Updates section in the Administration Guide.
Even if you upgrade one or two servers per week, you must wait until all servers in the group are upgraded before you update their firmware.
If your configuration is a dedicated private interconnect, disconnect the server from the Sun Ray interconnect.
See the Failover Groups chapter in the Administration Guide for a more general discussion of failover groups, including diagrams of failover topologies.