Why would you replace a host bus adapter host port?

You must replace a    when the existing HBA fails. Consider these items when replacing an HBA??host port:

• Depending on how the host is taken offline, ?? reservation data and registration data for the HBA host port that are no longer included in the configuration might be kept along with current reservation and registration data. Accumulation of old persistent reservation data eventually might cause the  to reach the upper boundary of permitted initiator ports. The RAID controller module also might send an Insufficient Registration Resources error if another HBA host port tries to register. The maximum number of persistent reservations per virtual disk depends on your system configuration. The maximum number of registrants per virtual disk is 512.
• To prevent an Insufficient Registration Resources error, you must remove the virtual disk reservations and registrations of the HBA host ports that are no longer included in the configuration. Remove virtual disk reservations only during scheduled maintenance downtimes to prevent interference with cluster server operations.