Using Serviceguard Extension for RAC, 9th Edition, September 2010

A Software Upgrades
Serviceguard Extension for RAC (SGeRAC) software upgrades can be done in the two following
ways:
• rolling upgrade
• non-rolling upgrade
Instead of an upgrade, moving to a new version can be done with:
• migration with cold install
Rolling upgrade is a feature of SGeRAC that allows you to perform a software upgrade on a given
node without bringing down the entire cluster. SGeRAC supports rolling upgrades on version
A.11.15 and later, and requires all nodes to be running on the same operating system revision
and architecture.
Non-rolling upgrade allows you to perform a software upgrade from any previous revision to
any higher revision or between operating system versions but requires halting the entire cluster.
The rolling and non-rolling upgrade processes can also be used any time one system needs to
be taken offline for hardware maintenance or patch installations. Until the upgrade process is
complete on all nodes, you cannot change the cluster configuration files, and you will not be able
to use any of the new features of the Serviceguard/SGeRAC release.
There may be circumstances when, instead of doing an upgrade, you prefer to do a migration
with cold install. The cold install process erases the preexisting operating system and data, and
then installs the new operating system and software. After a cold install, you must restore the
data. The advantage of migrating with a cold install is that the software can be installed without
regard for the software currently on the system or concern for cleaning up old software.
A significant factor when deciding to either do an upgrade or cold install is overall system
downtime. A rolling upgrade will cause the least downtime. This is because only one node in
the cluster is down at any one time. A non-rolling upgrade may require more down time, because
the entire cluster has to be brought down during the upgrade process.
One advantage of both rolling and non-rolling upgrades versus cold install is that upgrades
retain the preexisting operating system, software, and data. Conversely, the cold install process
erases the preexisting system—you must reinstall the operating system, software, and data. For
these reasons, a cold install may require more downtime.
The sections in this appendix are as follows:
• “Rolling Software Upgrades”
— “Steps for Rolling Upgrades ”
— “Example of Rolling Upgrade ”
— “Limitations of Rolling Upgrades ”
• “Non-Rolling Software Upgrades”
—
— “Limitations of Non-Rolling Upgrades ”
• “Migrating a SGeRAC Cluster with Cold Install”
Rolling Software Upgrades
SGeRAC version A.11.15 and later allow you to roll forward to any higher revision provided all
of the following conditions are met:
• The upgrade must be done on systems of the same architecture (HP 9000 or Integrity Servers).
• All nodes in the cluster must be running on the same version of HP-UX.
• Each node must be running a version of HP-UX that supports the new SGeRAC version.
• Each node must be running a version of Serviceguard that supports the new SGeRAC version.
Rolling Software Upgrades 131