fence_mpath fails to create persistent reservations on HP 3PAR VV devices in a Pacemaker cluster

Issue

• The fence_mpath fence agent fails to create persistent reservations on a HP 3PAR Virtual Volume (VV) device, even though there are currently no keys or reservations on the device:

  #  mpathpersist -ird /dev/mapper/mpatha
     PR generation=0x6d8, there is NO reservation held
  
  #  mpathpersist --out --reserve --param-rk=0x1 --prout-type=5 /dev/mapper/mpatha
     persistent reserve out: scsi status: Reservation Conflict
     PR out: command failed
  

• Unfencing a node fails when using fence_mpath with HP 3PAR VV devices, reporting the following error message on the cluster logs: "ERROR: Failed to verify x device(s)"