HP StorageWorks Fabric OS 6.x administrator guide (5697-7344, March 2008)

468 Configuring the PID format
In addition to the PID formats list here, Interoperability mode supports additional PID formats that are not
discussed in this guide.
Impact of changing the fabric PID format
If your fabric contains switches that use Native PID, it is recommended that you change the format to Core
PID before you add the new, higher port count switches and directors. Also, it is recommended that you use
Core PID when upgrading the Fabric OS version on 1Gb and 2Gb series switches.
Depending on your situation, the PID change might or might not entail fabric downtime:
• If you are running dual-fabrics with multipathing software, you can update one fabric at a time without
disrupting traffic. Move all traffic onto one fabric in the SAN and update the other fabric. Then move
the traffic onto the updated fabric, and update the final fabric.
• Without dual-fabrics, stopping traffic is highly recommended. This is the case for many routine
maintenance situations, so dual-fabrics are always recommended for uptime-sensitive environments. If
your fabric contains devices that employ static PID binding, or you do not have dual-fabrics, you must
schedule downtime for the SAN to change the PID format.
Host reboots
In some Fibre Channel SAN environments, storage devices and host servers are bound to the host
operating system by their PIDs (called their Fibre Channel addresses). In these environments, the hosts and
target HBAs in a SAN need to know the full 24-bit PIDs of the hosts and targets they are communicating
with, but they do not care how the PIDs are determined. But, if a storage device PID is changed, the host
must reestablish a new binding, which requires the host to be rebooted.
With the introduction of the Brocade 4/8 SAN Switch, 4/16 SAN Switch, SAN Switch 2/8V, SAN Switch
2/16V, SAN Switch 2/32, Brocade 4 Gb SAN Switch for p-Class BladeSystem, SAN Switch 4/32, SAN
Switch 4/32B, Core Switch 2/64, SAN Director 2/128, 4/256 SAN Director, and DC SAN Backbone
Director (short name, DC Director) the Native PID format used in earlier switches was supplemented with
the Core PID format, which is capable of addressing higher port counts. Changing from Native PID format
to Core PID format changes the PID, which requires hosts that use port binding to be rebooted.
Static PID mapping errors
If you can avoid using drivers that employ static PID binding, you should do so.
With the WWN or dynamic PID binding most typically used with drivers, changing the device’s PID does
not affect the PID mapping. However, before updating the PID format, it is necessary to determine whether
any devices in the SAN use static PID binding.
For those few drivers that do use static PID binding, changing the PID format breaks the mapping, which
must be fixed either by rebooting the host or by using a manual update procedure on the host.
To correct mapping errors caused by static PID binding, see the following sections:
• See ”Evaluating the fabric” on page 470 for details on finding devices that use static PID binding. Then
see ”Online update” on page 472 or ”Offline update” on page 473 for recommendations.
• See ”Converting port number to area ID” on page 474 for instructions.