Installation manual

Preparing to Upgrade in an OpenVMS Cluster Environment

6.5 Rolling Upgrade

This section describes the following:

• How a rolling upgrade works

• Notes and restrictions

• Tasks you need to perform to prepare your system for a rolling upgrade

6.5.1 How a Rolling Upgrade Works

During a rolling upgrade, you upgrade each system disk individually, allowing

old and new versions of the operating system to run together in the same cluster,

creating a mixed-version cluster. Because rolling upgrades allow mixed-version

clusters, the systems that you are not upgrading remain available.

6.5.2 Notes and Restrictions

The following restrictions apply to rolling upgrades:

• Compaq recommends that all VAX computers in a cluster run the same

version of the operating system. Mixed-version clusters are supported only

for the purpose of upgrading the entire cluster incrementally. Compaq further

recommends that all VAX systems in an OpenVMS Cluster run the latest

version of the OpenVMS VAX operating system.

• A rolling upgrade does not apply when all systems boot from a single system

disk. When all systems boot from a single system disk, perform a concurrent

upgrade using the procedure described in Section 6.4.

• During the rolling upgrade, the queuing system is disabled on the nodes being

upgraded. The queuing system on the other nodes should be unaffected by

the upgrade as long as a START/QUEUE/MANAGER/ON=(upgrade

node . . .) command is not executed. A START/QUEUE/MANAGER

command could attempt to move the queue manager process to the node

being upgraded if the /ON qualiﬁer indicates that it is one of the preferred

nodes. If the queue manager attempts to run on the node being upgraded, the

queuing system will hang on the entire cluster.

If your startup ﬁle contains a START/QUEUE/MANAGER/ON=(upgrade

node1, node2 . . . noden) command, do not boot in any nonupgrading

nodes until you have removed that command from the startup ﬁle.

Booting in a node causes the queuing system to hang on the cluster if the

START/QUEUE/MANAGER/ON=(upgrade node, . . . ) command is executed.

When the upgrade has completed, you can add the command back to the

startup ﬁle.

If the cluster queuing system hangs during the upgrade, it is most likely

caused by the queue manager attempting to run on the upgrading node. To

clear the condition, move the queue manager to a node you are not upgrading

by entering the following command:

START/QUEUE/MANAGER/ON=(nonupgrading node1, -

node2 . . . noden)

6–4 Preparing to Upgrade in an OpenVMS Cluster Environment