I am searching for specific criteria/events that will cause Windows 2008 to mark a SAN volume as offline in disk management, even though it is connected to that SAN volume via FC or iSCSI.

Microsoft states that "A dynamic disk may become Offline if it is corrupted or intermittently unavailable. A dynamic disk may also become Offline if you attempt to import a foreign (dynamic) disk and the import fails. An error icon appears on the Offline disk. Only dynamic disks display the Missing or Offline status."

I am specifically wondering if, on the SAN, changing the path to the disk (such as the disk being presented to the host via a different iSCSI target IQN or a different LUN #) would cause a volume to be offlined in disk management.


Edit: I have already found two reasons why a disk might be set offline, disk signature collisions and the SAN disk policy. Bounty would be awarded to someone who can find further documented reasons related to changes in the volume's path.

Disk signature collisions: http://blogs.technet.com/b/markrussinovich/archive/2011/11/08/3463572.aspx SAN disk policy: http://jeffwouters.nl/index.php/2011/06/disk-offline-with-error-the-disk-is-offline-because-of-a-policy-set-by-an-administrator/

  • How are you connecting to these disks? Are you using Microsoft's iSCSI Initiator? – JohnThePro May 10 '12 at 21:52
  • Yes, Microsoft iSCSI initiator. – Jeremy May 11 '12 at 13:47

Just on the off chance the machine has cluster services installed and the SAN volume is offline with "the disk is offline because of a policy set by an administrator" error, then check if the cluster service is started and if it is, whether the relevant cluster group is online.

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