Evaluating Your Configuration - HP 4400 Software Manual

5. To review update recommendations for your switches and HBAs, select the applicable folder
on the left side of the window. In
Look for the group name you created in step 2 of
The Best Practices and Recommendations window opens
Figure 6 Sample SAN Recommendations
If the firmware or driver version recommended is later than what is currently running, ensure
that you upgrade the appropriate switch or HBA.
NOTE: After completing required upgrades, HP recommends that you create a new SAN Visibility
report to verify that all upgrades were successful.

Evaluating your configuration

Consider the following factors when determining if an online upgrade is appropriate for your
environment:
Queuing host I/O—After the upgrade, the array performs a resynchronization. During the
resynchronization, host I/O is queued to the host, which can create a backlog of requests for
processing when the array is able to respond. The resynchronization may take less than a
minute, but it may take time to clear the backlog of requests and some host I/O may experience
timeouts. The HP recommended driver timeout value is 60 seconds. When an I/O timeout
occurs, multipath drivers typically retry the I/O request on the same or an alternate path.
These retry algorithms have operating system and HBA dependencies and may extend the
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. To ensure that host I/O from business
20 Preparing for the upgrade
Figure 5 (page 19), it is the folder called MySwitchGroup.
"Using SAN Visibility" (page 13).
(Figure 6 (page 20)).