HP StorageWorks 2/16V HP StorageWorks Fabric OS 5.X Procedures User Guide (AA- - Page 213

A Configuring the PID format Port identifiers (PIDs) are used by the routing and zoning services in Fibre Channel fabrics to identify ports in the network. All devices in a fabric must use the same PID format, so when you add new equipment to your SAN, you might need to change the PID format on legacy equipment. About PIDs and PID binding The PID is a 24-bit address built from three 8-bit fields: • domain • area_ID • AL_PA Many scenarios cause a device to receive a new PID, for example, unplugging the device from one port and plugging it into a different port as part of fabric maintenance, or changing the domain ID of a switch, which might be necessary when merging fabrics, or changing compatibility mode settings. Some device drivers use the PID to map logical disk drives to physical Fibre Channel counterparts. Most drivers can either change PID mappings dynamically (called dynamic PID binding) or use the WWN of the Fibre Channel disk for mapping (called WWN binding). Some older device drivers behave as if a PID uniquely identifies a device (they use static PID binding). These device drivers should be updated, if possible, to use WWN or dynamic PID binding instead, because static PID binding creates problems in many routine maintenance scenarios. Fortunately, very few device drivers still behave this way. Many current device drivers enable you to select static PID binding as well as WWN binding. Select static binding only if there is a compelling reason, and only after you have evaluated the impact of doing so. Summary of PID formats HP StorageWorks switches employ these types of PID formats: • VC encoded: The format defined by the Fibre Channel Storage Switch 8 and Fibre Channel Storage Switch 16. Connections to these switches are not supported in Fabric OS 4.0.0 and later. • Native: Introduced with the StorageWorks 1 GB switches, this format supports up to 16 ports per switch. • Core: The default for the 4/8 SAN Switch, 4/16 SAN Switch, SAN Switch 2/8V, SAN Switch 2/16V, SAN Switch 2/32, Brocade 4Gb SAN Switch for HP p-Class BladeSystem, SAN Switch 4/32, Core Switch 2/64, SAN Director 2/128, and 4/256 SAN Director and is the recommended format for HP StorageWorks switches and fabrics. It uses the entire 8-bit address space and directly uses the port number as the area_ID. It supports up to 256 ports per switch. • Extended edge: This format generates the same PID for a port on switches with 16 or fewer ports as would native PID format, but it also supports up to 256 ports per domain. It should be used only in cases where you cannot upgrade devices to dynamic PID binding and you absolutely cannot reboot your servers. Extended edge PID is supported in Fabric OS 2.6.2 and later, 3.1.2 and later, and 4.2.0 and later. 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, HP recommends that you change the format to Core PID before you add the new, higher port count switches and directors. HP recommends that you use Core PID when upgrading the Fabric OS version on HP StorageWorks 1 GB and 2 GB switches. Depending on your situation, the PID change might or might not entail fabric downtime: Fabric OS 5.x administrator guide 213