Using Serviceguard Extension for RAC Version A.11.20 - (August 2011)

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.
During rolling upgrade the nodes can run on mixed version of HP-UX. Rolling upgrades are not
intended as a means of using mixed release of HP-UX with in the same cluster. HP recommends to
upgrade all the cluster nodes to the new release level at the earliest.
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” (page 139)
“Steps for Rolling Upgrades ” (page 142)◦
◦ “Example of Rolling Upgrade ” (page 143)
◦ “Limitations of Rolling Upgrades ” (page 147)
• “Non-Rolling Software Upgrades” (page 148)
◦ “Limitations of Non-Rolling Upgrades ” (page 148)
• “Migrating an SGeRAC Cluster with Cold Install” (page 148)
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.
Rolling Software Upgrades 139