HP BA322 90087 - Manual (Page 101)

After the shutdown procedure is finished on all nodes, go to Chapter 6 (page 103) to begin the
upgrade procedure.
CAUTION: During the upgrade it is very important that the system disk being upgraded is
accessed only by the node on which the upgrade is being performed. If the disk can be accessed
from other nodes in the cluster, for example, through an HSC or HSJ device, you must ensure
that this does not happen. Even if the disk is only mounted and no file access is performed, the
disk can still become corrupted.
Ensure that any users who might mount disks know that they must not access the system disk
being upgraded. Also make sure that any procedures that might mount the disk do not run
during the upgrade. If you have automatic procedures that periodically check and remount disks,
it would be wise to disable them during the upgrade.
5.5 Types of Upgrades 101