Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

403Administering cluster functionality
Upgrading cluster functionality
Upgrading cluster functionality
The rolling upgrade feature allows you to upgrade the version of VxVM running in a
cluster without shutting down the entire cluster. To install the new version of VxVM
running on a cluster, make one node leave the cluster, upgrade it, and then join it back into
the cluster. This operation is repeated for each node in the cluster.
Note: Rolling upgrade is supported for the cluster functionality of VxVM, but may not be
supported for other software components (such as CFS) if these have been installed.
Consult the release notes that accompany that product for more information.
Each Veritas Volume Manager release starting with Release 3.1 has a cluster protocol
version number associated with it. The cluster protocol version is not the same as the
release number or the disk group version number. The cluster protocol version is stored in
the /etc/vx/volboot file. During a new installation of VxVM, the
vxdctl init
command creates the volboot file and sets the cluster protocol version to the highest
supported version.
Each new Veritas Volume Manager release supports two cluster protocol versions. The
lower version number corresponds to a previous Veritas Volume Manager release. This
has a fixed set of features and communication protocols. The higher version number
corresponds to the new release of VxVM which has a new set of these features. If the new
release of VxVM does not have any functional or protocol changes, but only bug fixes or
minor changes, the cluster protocol version remains unchanged. In this case, the cluster
protocol version does not need to be upgraded.
During a rolling upgrade, each node must be shut down and the Veritas Volume Manager
release with the latest cluster protocol version must be installed. All nodes that have the
new release of VxVM continue to use the lower level version. A slave node that has the
new cluster protocol version installed tries to join the cluster. If the new cluster protocol
version is not in use on the master node, it rejects the join and provides the current cluster
protocol version to the slave node. The slave retries the join with the cluster protocol
version provided by the master node. If the join fails at this point, the cluster protocol
version on the master node is out of range of the protocol versions supported by the
joining slave. In such a situation, you must upgrade the remainder of the cluster through
each intermediate release of VxVM to reach the latest supported cluster protocol version.
Once you have installed the new release on all nodes, run the
vxdctl upgrade command
on the master node to switch the cluster to the higher cluster protocol version. See
“Upgrading the cluster protocol version” on page 414 for more information.