Disks offline after a Hyper-V IR


Some Guest VM disks go offline after a Hyper-V IR has completed.



To explain how to resolve an issue where disks are offline for some Windows servers after they are recovered through Hyper-V instant recovery in audit or instant recovery mode.


This problem occurs only when performing a Hyper-V instant recovery. (It does not occur when performing a VM restore.)  It affects only Windows server VMs meeting all of the following criteria:

  • The servers have multiple SCSi controllers.
  • Multiple disks reside on each controller.
  • The location number for a disk on one controller is the same as the location number for a disk on another controller.

For example, a Windows server with the following disk configuration would be affected:

  • SCSi controller 1 with disks residing in locations 1, 2, and 3.
  • SCSi controller 2 with disks residing in locations 1, 4, and 5.

After the recovery, all three disks for SCSi controller 1 would be online, and disks in locations 4 and 5 for controller 2 would also be online.  However, the disk in location 1 on controller 2 would be offline.


You can resolve this issue by accessing Disk Management on the server VM, right-clicking on the disk in an offline state, and then clicking Online.  Procedures may vary slightly depending on the server version.

 For more information about Hyper-V instant recovery, see Instant recovery for Hyper-V in the Unitrends Recovery-Series and UEB Adminstrator’s Guide.

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