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ReFS and Hyper-V VHD

    Question

  • For a new Hyper-V cluster (server 2012 R2) what are the benefits and drawbacks of using ReFS for the Hyper-V VHD drive?

    Friday, November 22, 2013 5:12 PM

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  • For a new Hyper-V cluster (server 2012 R2) what are the benefits and drawbacks of using ReFS for the Hyper-V VHD drive?

    The only real benefit you'll have is a strong checksum protection for metadata (always) and data (optional). So with a proper underlying storage stack (Clustered Storage Spaces) ReFS will always report data corruption and will try to fix errors doing remap @ file system level reading alive copy of your data. Also you'll avoid long time needed to run chkdsk if all nodes of the cluster will go AWOL unexpectedly (rare case for a cluster in any case...). No other benefits so far... There's still no dedupe with ReFS but it does not work for live data either way and you'll have to stick enabling dedupe inside a VM (not very efficient to say at least).

    StarWind iSCSI SAN & NAS

    Friday, November 22, 2013 8:00 PM
  • Hi,

    ReFS doesn’t need CHKDSK because repair functionality is built-into the file system.

    Some key capabilities missing from ReFS as compared to NTFS are EFS encryption, quotas, and compression. BitLocker may be used for encrypting these volumes while EFS is not an option.

    More detail please the following article:

    Windows Server 2012: Does ReFS replace NTFS? When should I use it?

    http://blogs.technet.com/b/askpfeplat/archive/2013/01/02/windows-server-2012-does-refs-replace-ntfs-when-should-i-use-it.aspx

    Hope this helps.


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    Monday, November 25, 2013 8:31 AM
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  • This is good information, but I am still not sure if it will be good for my hyper-v VHDs or Starwind .img san files.  I think it sounds like it would work well, as they will be fairly large files that will need to be "always on" and will not have the down time needed to CHKDSK the drives, but I need to make sure it will not create any conflicts with Hyper-V or my Starwind San software,
    Monday, November 25, 2013 5:27 PM
  • Hi ChrisPCPS,

    StarWind's .img is only a container to allocate data on the disk so it's transparent to the client OS. 

    There is technically no way for a VHD to conflict with StarWind's .img files.

    Tuesday, November 26, 2013 10:18 AM
  • I was more worried about the ReFS conflicting with either the VHD or the .img.

    Tuesday, November 26, 2013 3:33 PM
  • I was more worried about the ReFS conflicting with either the VHD or the .img.

    There are no conflicts. ReFS is good to detect silent data corruption. So if you're using plain StarWind images and not LSFS (Log-Structured File System, that one comes with a much superior set of a protective features also including strong checksums for every data / metadata stream) - stick with ReFS instead of NTFS. Performance for ReFS is irrelevant as StarWind does own caching (system routines are not used).

    StarWind iSCSI SAN & NAS

    Tuesday, November 26, 2013 6:36 PM