What is Persistent Binding? What are the advantages of Persistent Binding?

How does Persistent Binding Work?
 

A fibre channel target is assigned its World Wide Node Name (WWNN) at loop initialization time; the SCSI target ID for that target is assigned by the device driver when the device is first discovered. It is possible for the WWNN to change between one loop initialization and the next. Every time a system boots or a target is added to or removed from the fibre channel, the loop will be re-initialized. After a system has booted, it will maintain a constant view of the same target ID because the driver software remaps the SCSI target ID to the new WWNN on the fly.
 

In an environment that utilizes persistent binding, once a system has booted, it will maintain a constant view of the same target ID because the driver software remaps the SCSI target ID to the new WWNN on the fly.
 

 

Persistent Binding Advantages:
 

A second system may use a different SCSI target ID for that target. Thus, an administrator seeking to work with the same target across multiple hosts must be prepared to encounter the situation where the same fibre channel target is known by different SCSI target IDs. Use persistent binding to maintain a consistent target ID on all systems. A common scenario for this type of situation would be a network administrator who needs to consistently map to a tape drive for backup purposes.
 

Please refer to this Emulex article for additional information:  

https://www-dl.emulex.com/support/utilities/hbanyware/40/hbanyware.pdf