HP StorageWorks MSA 2/8 HP StorageWorks Fabric OS Procedures V3.1.x/4.1.x User - Page 146

Updating Switches to the Core PID Addressing Note: It is recommended not to use drivers that bind by PID. There are several routine maintenance procedures which may result in a device receiving a new PID. Refer to About PID Mapping for more information. About PID Mapping A PID is a Port Identifier. PIDs are used by the routing and zoning services in Fibre Channel fabrics to identify ports in the network. They are not used to uniquely identify a device; this is done using the World Wide Name (WWN). Some device drivers map logical disk drives to physical Fibre Channel counterparts by PID. An example in a Windows HBA driver is "Drive E: = PID 011F00". Most drivers can either dynamically change PID mappings or use the WWN of the Fibre Channel disk for mapping, not the PID. For example, "Drive E: = WWN 10:00:00:60:69:51:0e:8b". Dynamic PID WWN or dynamic PID binding is most typically used. In this case, changing the device's PID does not affect the mapping. However, before updating the PID format, it is necessary to determine whether or not any devices in the SAN bind by PID (see Evaluate the Fabric). Static PID For those few drivers that use static PID binding, when the format is changed (PID 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. To manually correct broken mapping due to static PIDs, refer to the following sections for more detail: ■ Evaluate the Fabric of this chapter 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 is chosen to perform the actual update. ■ Frequently Asked Questions provides a Q&A format to discuss the issues surrounding a core PID format update. 146 Fabric OS Procedures Version 3.1.x/4.1.x User Guide