HP AA-RS2WC-TE Installation Manual page 185

In new installations, the PID format should always be set to the new addressing
method before the fabric enters production. When updating an existing SAN,
there are several scenarios which must be evaluated before changing the PID
format.
Proactively setting the core PID format on all new fabrics before they enter
production will prevent the need to update those fabrics in the future. This is
strongly recommended as a step in the deployment of all new fabrics. There is no
difference in the behavior of a fabric with either PID format; changing to the new
format during deployment will merely save administrative effort later on.
Some device drivers map logical disk drives to physical Fibre Channel
counterparts by PID.
An example in a Windows HBA driver is:
Most drivers can either dynamically change PID mappings or use the WWN of the
Fibre Channel disk for mapping, not the PID, as shown in the following example:
For those few drivers that use static PID binding, when the format is changed
(PID à 010F00), the mapping breaks and must be manually fixed. (The driver still
has "Drive E: = PID 011F00" but the actual device address is now "010F00") This
can be done by rebooting the host, or using a manual update procedure on the
host. This is discussed in more detail in the following sections.
In the more typical case where WWN or dynamic PID binding is used changing
the device's PID does not affect the mapping, but before updating the PID format,
it is necessary to determine whether or not any devices in the SAN bind by PID.
In every case where devices bind by PID, any such procedure will become
difficult or impossible to execute without downtime. In some cases, device drivers
allow the user to manually specify persistent bindings by PID. In these cases, such
devices must be identified and an appropriate update procedure created. If
possible, the procedure should involve changing from PID binding to WWN
binding. The Recommended Approaches section of this section discusses in more
detail the process of updating to the new PID format. This starts with evaluating a
production SAN to see which if any devices bind by PID. Then either an online or
offline update procedure will be chosen to perform the actual update.
The Frequently Asked Questions section provides a Q&A format to discuss the
issues surrounding a core PID format update. Finally, the Detailed Procedures
section provides examples of step-by-step instructions for certain PID-bound
Core Switch 2/64 V4.1 Installation Guide
Drive E: = PID 011F00
Drive E: = WWN 10:00:00:60:69:51:0e:8b
Technical Specifications
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