HP A7533A - Brocade 4Gb SAN Switch Base Administrator's Manual page 455

1. Collect device, software, hardware, and configuration data.
The following is a non-comprehensive list of information to collect:
• HBA driver versions
• Fabric OS versions
• RAID array microcode versions
• SCSI bridge code versions
• JBOD drive firmware versions
• Multipathing software versions
• HBA time-out values
• Multipathing software timeout values
• Kernel timeout values
• Configuration of switch
2. Make a list of manually configurable PID drivers.
Some device drivers do not automatically bind by PID, but allow the operator to manually create a PID
binding. For example, persistent binding of PIDs to logical drives might be done in many HBA drivers.
Make a list of all devices that are configured this way. If manual PID binding is in use, consider
changing to WWN binding.
The following are some of the device types that might be manually configured to bind by PID:
• HBA drivers (persistent binding)
• RAID arrays (LUN access control)
• SCSI bridges (LUN mapping)
3. Analyze data.
After you have determined the code versions of each device on the fabric, they must be evaluated to
find out if any automatically bind by PID. It might be easiest to work with the support providers of these
devices to get this information. If this is not possible, you might need to perform empirical testing.
Binding by PID can create management difficulties in a number of scenarios. It is recommended that
you not use drivers that bind by PID. If the current drivers do bind by PID, upgrade to WWN-binding
drivers if possible.
The drivers shipping by default with HP/UX and AIX bind by PID, and so detailed procedures are
provided for these operating systems in this chapter. Similar procedures can be developed for other
operating systems that run HBA drivers that bind by PID.
There is no inherent PID binding problem with either AIX or HP/UX. It is the HBA drivers shipping with
these operating systems that bind by PID. Both operating systems are expected to release HBA drivers
that bind by WWN, and these drivers might already be available through some support channels.
Work with the appropriate support provider to find out about driver availability.
It is also important to understand how multipathing software reacts when one of the two fabrics is taken
offline. If the time-outs are set correctly, the failover between fabrics should be transparent to the users.
You should use the multipathing software to manually fail a path before starting maintenance on that
fabric.
4. Perform empirical testing.
Empirical testing might 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 procedure in
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.
"Changing the PID format
Fabric OS 6.1.x administrator guide 455
online" on page 456.