HP StorageWorks 2.128 SAN Director Switch - Manual (Page 218)

218 Configuring the PID format
If either of the first two options are used, the procedures should again be validated in the test
environment.
Determine the behavior of multipathing software, including but not limited to:
• HBA time-out values
• Multipathing software time-out values
• Kernel time-out values
Planning the update procedure
Whether it is best to perform an offline or online update depends on the uptime requirements of the site.
• An offline update requires that all devices attached to the fabric be offline.
• With careful planning, it should be safe to update the core PID format parameter in a live, production
environment. This requires dual fabrics with multipathing software. Avoid running backups during the
update process, as tape drives tend to be very sensitive to I/O interruption. The online update process
is intended for use only in uptime-critical dual-fabric environments, with multipathing software
(high-uptime environments should always use a redundant fabric SAN architecture). Schedule a time
for the update when the least critical traffic is running.
All switches running any version of Fabric OS 3.1.2 and later or 4.2.0 and later are shipped with the
Core PID format enabled, so it is not necessary to perform the PID format change on these switches.
Migrating from manual PID binding (such as persistent binding on an HBA) to manual WWN binding
and upgrading drivers to versions that do not bind by PID can often be done before setting the core PID
format. This reduces the number of variables in the update process.
Online update
The following steps are intended to provide SAN administrators a starting point for creating site-specific
procedures.
1. Back up all data and verify backups.
2. Verify that the multipathing software can switch over between fabrics seamlessly. If there is doubt, use
the software’s administrative tools to manually disassociate or mark offline all storage devices on the
first fabric to be updated.
3. Verify that I/O continues on the other fabric.
4. Disable all switches in the fabric to be updated, one switch at a time, and verify that I/O continues on
the other fabric after each switch is disabled.
5. Change the PID format on each switch in the fabric.
6. Reenable the switches in the updated fabric one at a time.
In a core/edge network, enable the core switches first.
7. After the fabric has reconverged, use the
cfgEnable
command to update zoning.
8. Update the bindings for any devices manually bound by PID.
This might involve changing them to the new PIDs, or preferably changing to WWN binding.
For any devices bound by PID, two options exist:
• Execute a custom procedure to rebuild the device tree online. Examples are provided in the
” Converting port number to area ID ” on page 222 section of this chapter.
• Reboot the device to rebuild the device tree. Some operating systems require a special command
to do this, for example
boot –r
in Solaris.
9. For devices that do not bind by PID or have had their PID binding updated, mark online or reassociate
the disk devices with the multipathing software and resume I/O over the updated fabric.
10. Repeat this procedure with the other fabrics.
Offline update
The following steps are intended to provide SAN administrators a starting point for creating site-specific
procedures.