Hyper-V: Troubleshooting Snapshot Failure

Hyper-V: Troubleshooting Snapshot Failure


Snapshots fail to merge with error 0x80070070

Applies to: Windows Server 2008, Windows Server 2008 R2 


Snapshots fail to merge with error


Low disk space.


Create additional free disk space to allow the merge to complete, or move the .VHD and .AVHD file to a volume with sufficient disk space, and then manually merge the snapshots.

Note: Snapshots based on fixed .VHD files hold the free space that has been pre-provisioned inside the fixed VHD. Snapshots are dynamically expanding by nature and running a fixed-VHD VM on a snapshot for a long time means you lose the performance benefits of fixed VHD files. You should commit the data in the snapshot as soon as possible after it has served its purpose.

Let me add a few cautions here.

If you have simply copied the virtual disks to different drives on the same server and reconfigured the VM to use the latest snapshot, the original disks are still being used by the VM.

Therefore manually copying the virtual disks means that you need to fix each snapshot disk in the chain to make sure that it is pointing to its correct parent.

If you used Storage Migration to move the virtual disks - bonus points for you!  You did the right thing.

The I/O device error can be any number of things.  Searching points to try running chkdsk on the volume and see if there is anything that can be repaired.

The Server taking a long time to start - that can be an indicator of a storage issue (controller, disks, etc.)  Or some large background task that is attempting to happen again.  Which could be anything.

Martini Jones (MCP,CCNA,CCNP)
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