8100 Updating Product Software Guide (XCS 6.250) (5697-1716, February 2012)

time that host I/O will be allowed to complete successfully beyond the 60-second timeout.

Additionally, some applications may be more sensitive to I/O delays.

• Processing host I/O during the upgrade—The upgrade competes with host requests that have

a higher priority, which can affect the upgrade outcome. Select a time for the upgrade when

host I/O is at a minimum.

• Communicating with HP P6000 Command View—The first steps of the upgrade have a lower

priority than host I/O. The upgrade can extend beyond the timeout values expected by HP

P6000 Command View, which may cause loss of management connectivity to the EVA. An

HP P6000 Command View discover operation may be required to re-establish communication

with the EVA.

XCS 6.250 upgrade considerations

Before upgrading to XCS 6.250, consider the following:

• When performing an online upgrade, to ensure a resynchronization time of less than 60

seconds, the total allocated capacity should be 10 TB or less and the configuration cannot

contain DR groups. Upgrades in HP P6000 Continuous Access configurations should be

performed offline. Allocated capacity is the total of all virtual disks, snapshots, snapclones,

mirrorclones and containers.

NOTE: This is not a regression of support. It is a formal statement of limitations that have

been in effect for previous releases.

• Check the disk group occupancy alarm setting before upgrading disk drive software. See the

HP Enterprise Virtual Array best practices configuration white paper for guidelines on how to

configure this setting based on your capacity. Locate the white paper for your array model

at:

http://h18006.www1.hp.com/storage/arraywhitepapers.html

• HP test results show that upgrading the controller software online on an EVA containing Vraid0

LUNs can marginally increase the possibility of Vraid0 LUN data unavailability during the

upgrade. To reduce this increased risk, either halt all host I/O to Vraid0 LUNs or migrate the

LUNs to another Vraid level before the upgrade.

• Stop all storage modification jobs (such as creation, deletion, presentation) 30 minutes before

beginning the controller software upgrade.

• Check that all switch ports (either on a switch connected to the array or on the EVA4400

embedded switch controllers) are set to the HP recommended setting of auto-negotiate.

Selecting an appropriate time to perform an online upgrade

To ensure the success of an online upgrade, selecting the appropriate time is essential. The two

factors that most affect this selection are:

• Criticality of business applications—Do not select a time that could affect critical business

applications.

• I/O load—Select a period of low I/O activity to ensure that the upgrade is completed as

quickly as possible, and to avoid disruptions to host and applications due to timeouts.

While there are advantages to performing an online upgrade, there are circumstances when it is

not advisable. Therefore, give careful consideration to the circumstances of your configuration and

application deployment before making an attempt to do an online upgrade.

NOTE: When determining an appropriate time to do an online upgrade, ensure that no

configuration-related replication tasks are in process (creating or deleting DR groups, snapshots,

snapclones, mirrorclones or presenting to hosts).

22 Pre-upgrade tasks