Issue

• The system hung, or file systems are no longer accessible.
• Unable to write to one or more filesystems.
• Server appears to have spontaneously rebooted

• The console and /var/log/messages logs show messages like:

  scsi4 (0:0): rejecting I/O to offline device
  [ ... ]
  sd 1:0:0:5: [sdf] Warning! Received an indication that the LUN assignments on this target have changed. The Linux SCSI layer does not automatically remap LUN assignments.
  [ ... ]
  sd 1:0:0:2: rejecting I/O to offline device
  [ ... ]
  sd 1:0:0:4: Device offlined - not ready after error recovery
  [ ... ]
  EXT3-fs (server): I/O error while writing superblock
  [ ... ]
  JBD: Spotted dirty metadata buffer (dev = server, blocknr = 0). There's a risk of filesystem corruption in case of system crash.