SCSI error: return code = 0x00000018 and "scsi reservation conflict" with High Availibility AddOn

Issue

• /var/log/messages reports errors similar to:

  Nov  7 05:15:25 hostname kernel: sd 0:0:1:0: reservation conflict
  Nov  7 05:15:25 hostname kernel: sd 0:0:1:0: SCSI error: return code = 0x00000018
  

• or

  Oct 20 18:17:20 hostname kernel: scsi1 (0,5,0) : reservation conflict
  Oct 20 18:17:20 hostname kernel: SCSI error : <1 0 5 0> return code = 0x18
  Oct 20 18:17:20 hostname kernel: end_request: I/O error, dev sdg, sector 1331359
  

• When these errors are seen, the following symptoms have been reported

  • SCSI Reservation Conflicts
  • Devices will not mount
  • File systems may be set to Read Only
  • Commands that access shared storage are taking a long time to complete, or fail

• Other symptoms include

  • System hangs during boot when fiber-channel LUNs are presented and "reservation conflict" messages
  • GFS file system will not mount, followed by reservation conflicts.