Cold VHDs missing from Data Deduplicated storage volume


  • This has happened to us twice now. It seems as though whenever the deduplication garbage collection runs on our Server 2012 R2 Hyper-V host, the VHDs from all cold (Not turned on) VMs disappear.

    The VMs are still visible in Hyper-V Manager, but their disks are gone off the storage volume.

    Does anybody have any idea why this might be happening?

    Saturday, October 26, 2013 2:47 PM


  • Hi,

    Thank you for posting your question. This is indeed very interesting. There are no limitations for deduplicating volumes with turned off VM’s VHD/VHDX files. Live file support for dedup is only limited to VDI. Even if this would be somehow caused by dedup alone I would still understand any form of corruption, but files disappearing is very strange. One could turn on audit on the files; I would rather suspect an interfering driver able to interact on the IO stack. This could be anything installed from antivirus software to any backup solution, encryption software or basically any driver loaded.


    Monday, October 28, 2013 3:23 PM

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