HP 3PAR Upgrade Pre-Planning Guide

5 Symantec Veritas Storage Foundation DMP (VxDMP) and
Online Upgrade
NOTE: For hosts running RHEL 6 or SLES 11 with Storage Foundation VxDMP 6.0.x, only offline
upgrades are supported when upgrading from HP 3PAR OS 2.3.1 to HP 3PAR OS 3.1.1.
NOTE: HP 3PAR OS online upgrades with attached hosts using Symantec Veritas Storage
Foundation VxDMP multipath software require a pause to be implemented between upgrades of
the array nodes within the system. The pause is to be implemented in order to allow sufficient time
for I/O path recovery to maintain host connectivity to all presented volumes. HP 3PAR testing
indicates that a pause of 5 minutes between array node upgrades is sufficient to allow VxDMP
I/O path recovery during the upgrade.
Pauses exceeding 30 minutes are not recommended.
A pause between array node upgrades can only implemented while performing node-by-node
online upgrades with the Advanced/manual procedures for HP 3PAR OS 3.1.1 and later. Failure
to utilize the node-by-node online upgrades procedures and implement a pause between array
node upgrades may result in loss of host connectivity and data availability of Veritas disks or disk
groups during the array upgrade.
The default value of the VxDMP link restore (dmp_restore_interval tunable) interval must temporarily
be changed to a value of 1 second before performing an online upgrade of the HP 3PAR OS for
the following VxDMP versions:
• All Linux/Solaris/AIX VxDMP versions older than 5.0MP1
• All NetApp VxDMP versions older than 5.0MP3
Changing the link restore interval causes the VxDMP software to react to the return of missing paths
more quickly than it normally would with default settings. Failure to perform the change to the
shorter restore interval for the noted VxDMP versions above, may cause a loss of host connectivity
to HP 3PAR volumes during the upgrade. For instructions, see “Changing the Veritas DMP Link
Restore Interval” (page 22). After the online upgrade, reset the link restore interval to the previously
configured value. For instructions, see “Restoring the Veritas DMP Link Restore Interval” (page 23).
As of VxDMP 5.0MP1 for Linux/Solaris/AIX and 5.0MP3 NetApp, Veritas software was modified
to circumvent the path loss issue related to the link restore interval during an HP 3PAR OS upgrade
and no changes to the restore interval are necessary.
Changing the Veritas DMP Link Restore Interval
The following procedure may be required if you are performing an online upgrade to the HP 3PAR
OS and Veritas DMP is being used for the multipathing solution on the host. The procedure must
be repeated for each host server that is connected to the HP 3PAR StoreServ Storage and using
Veritas DMP.
Use the following procedure to gather the current settings and change the link restore interval:
1. Display the current setting of the link restore interval as follows. Record the interval so that it
can be restored later.
# vxdmpadm stat restored (note the current setting)
2. Stop the daemon.
# vxdmpadm stop restore
22 Symantec Veritas Storage Foundation DMP (VxDMP) and Online Upgrade