Seeing message: "sd 2:0:0:0: rdac: LUN 0 (RDAC) (unowned)" in dmesg

Solution Unverified - Updated

Environment

  • Red Hat Enterprise Linux 6.2

Issue

  • When udev starts and sees the SAN drives it begins trying to access them and receives I/O errors.
  • It is slowing down boot time tremendously.
  • Seen in dmesg:
device-mapper: multipath: version 1.3.0 loaded
sd 2:0:0:0: rdac: LUN 0 (RDAC) (unowned)
sd 2:0:0:1: rdac: LUN 1 (RDAC) (owned)
sd 2:0:0:2: rdac: LUN 2 (RDAC) (unowned)
sd 2:0:0:3: rdac: LUN 3 (RDAC) (owned)

Resolution

  • From dmesg:
sd 2:0:0:0: rdac: LUN 0 (RDAC) (unowned)
  • The messages exist only for unowned paths:
sd 2:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 2:0:0:0: [sdb] Sense Key : Illegal Request [current] 
sd 2:0:0:0: [sdb] <<vendor>> ASC=0x94 ASCQ=0x1ASC=0x94 ASCQ=0x1
sd 2:0:0:0: [sdb] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
end_request: I/O error, dev sdb, sector 0
Buffer I/O error on device sdb, logical block 0
  • Please add the following to kernel command line to specify module load order and see if issue persists: 
rdloaddriver=scsi_dh_rdac,mpt2sas
  • If the issue persists, please apply the errata fix located at the following link:

Root Cause

  • It would appear that the HBA driver is loading before the scsi_dh_rdac module is loading and setup IO (report luns, etc) are getting sent to unowned paths.
SBR
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