Use of Persistent Reserve

Starting GPFS version 3.2 (and higher releases), the introduction of Persistent Reserve (PR)

option reduces GPFS recovery time from node failures, thus allowing Oracle OCR ad VOTING

disks to be placed on a GPFS file system. Oracle RAC development team  strongly recommends

enabling GPFS 'Persistent Reserve' option when planning to have Oracle RAC OCR and

VOTING disks on a GPFS file system.

In the event of SAN connection failures across multiple nodes, if the second and any subsequent 

SAN failure occurs  while GPFS recovery is already in progress then the total GPFS recovery

time may exceed the default Oracle CSS misscount and results in additional node evictions.  To

protect against this multiple SAN failure scenario, customers can choose to locate the Oracle

OCR and Voting disks on raw devices, instead of on a GPFS file system.