HP StorageWorks MSA 2.8 SAN Switch - Manual (Page 150)

Updating Switches to the Core PID Addressing
150 Fabric OS Procedures Version 3.1.x/4.1.x User Guide
It is also important to understand how multi-pathing software reacts when one of
the two fabrics is taken offline. If the time-outs are set correctly, the switchover
between fabrics should be transparent to the users.
Note: It is recommended that you use the multi-pathing software to manually fail a
path before starting maintenance on that fabric.
Performing Empirical Testing
Empirical testing may be required for some devices to determine whether they
bind by PID. If you are not sure about a device, work with the support provider to
create a test environment.
Create as close a match as practical between the test environment and the
production environment and perform an update using the Online Update
procedure provided above.
Devices that bind by PID are unable to adapt to the new format, and one of three
approaches must be taken with them:
■ A plan can be created for working around the device driver’s limitations in
such a way as to allow an online update. See the Detailed Procedures section
for examples of how this could be done.
■ The device can be upgraded to drivers that do not bind by PID.
■ Downtime can be scheduled to reset the device during the core PID update
process, which generally allows the mapping to be rebuilt.
If either of the first two options are used, the procedures should again be validated
in the test environment.
Determine the behavior of multi-pathing software, including but not limited to:
■ HBA time-out values
■ Multi-pathing software time-out values
■ Kernel time-out values