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Volume Shadow Copies - Limited Number of Copies?

    Question

  • I have two servers that seem to be artificially limited on the number of copies:

    • Server 2008 R2 Service Pack 1
    • 6 copies
    • 50GB is allocated and plenty of disk space to use that much
    • 8GB in use

    • Server 2012 R2
    • 10 copies
    • 100GB is allocated and plenty of disk space to use that much
    • 10GB in use

    MaxShadowCopies is not configured on either. We do 2 copies a day. Neither seem to have skipped or missed a copy, but appear to just be "truncated" before they reached the disk limit.



    • Edited by laurin1 Monday, December 18, 2017 8:30 PM
    Wednesday, December 13, 2017 8:57 PM

All replies

  • Hi laurin1,

    The maximum number of software shadow copies for each volume is 512. However, by default you can only maintain 64 shadow copies that are used by the Shadow Copies of Shared Folders feature. To change the limit for the Shadow Copies of Shared Folders feature, use the MaxShadowCopies registry key. http://msdn.microsoft.com/en-us/library/bb891959(v=vs.85).aspx

    For more info: http://msdn.microsoft.com/en-us/library/aa384627(v=vs.85).aspx

    And based on my knowledge, sometimes since the shadowstorage, it may also limit the number.

    You could run the commands to do a check,

    vssadmin list shadowstorage

    https://technet.microsoft.com/en-us/library/cc788045(v=ws.11).aspx

    For increase the size of shadow copy, you could run:

    vssadmin resize shadowstoreage

    Best Regards,

    Mary


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    Thursday, December 14, 2017 3:08 AM
    Moderator
  • Yes, I read about those limitations, but I'm not sure how applies here. Right now, these 2 machines seem to be limited to 6-10 copies, not 64. What is limiting these to such a low number?

    C:\windows\system32>vssadmin list shadowstorage
    vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
    (C) Copyright 2001-2005 Microsoft Corp.

    Shadow Copy Storage association
       For volume: (C:)\\?\Volume{857e5fb6-6e69-11e3-9fdd-806e6f6e6963}\
       Shadow Copy Storage volume: (C:)\\?\Volume{857e5fb6-6e69-11e3-9fdd-806e6f6e6
    63}\
       Used Shadow Copy Storage space: 8.825 GB (0%)
       Allocated Shadow Copy Storage space: 11.046 GB (0%)
       Maximum Shadow Copy Storage space: 48.828 GB (2%)

    Thursday, December 14, 2017 1:15 PM
  • Hi,

    Please make sure the MaxShadowCopies  value has been set correct.

    And you have the enough space now? Could you test to try to choose No limit in Maximum size of Shadow Copies and see if more snapshots could be created. You could also manually create snapshots for testing.

    Best Regards,

    Mary


    Please remember to mark the replies as answers if they help.
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    • Marked as answer by laurin1 Thursday, December 21, 2017 6:24 PM
    • Unmarked as answer by laurin1 Friday, March 16, 2018 5:31 PM
    Friday, December 15, 2017 2:26 AM
    Moderator
  • Why do I need to set MaxShadowCopies? The value does not exist on either of these machines (on any of my servers, I believe).

    From the documentation:

    Create a value with the name MaxShadowCopies and type DWORD. The default data for this value is 64. The minimum is 1. The maximum is 512.

    So why is it not creating up to 64 copies, with only space being the limitation?

    Yes, there is plenty of space on both of the machines. I can create new copies manually, but for some reason, these machines won't create copies automatically up to their space limit.

    I'll set MaxShadowCopies to 64 and just see what happens.

    Friday, December 15, 2017 1:03 PM
  • Hi laurin1,

    >Yes, there is plenty of space on both of the machines. I can create new copies manually, but for some reason, these machines won't create copies automatically up to their space limit.

    And sometimes, even though you have the enough space for the disk. But the free space for shadow copy may still be limited.

    So I suggest you could set the value of  Maximum Shadow Copy Storage space to unbound to do a check.

    Best Regards,

    Mary


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    Monday, December 18, 2017 7:27 AM
    Moderator
  • What do you mean by "unbound"?
    Monday, December 18, 2017 12:21 PM
  • So I set it to 64, as I said, and now the number of copies are increasing, but why? What arbitrary limitation is keeping it from using 64 anyway?

    Also, and this is very strange, the usage on these jumped way up (not proportionally).

    • Server 2008 R2 Service Pack 1
    • 6 copies - now has 16
    • 50GB allocated
    • 8GB in use - now is 50GB!

    • Server 2012 R2
    • 10 copies - now has twice that
    • 100GB is allocated
    • 10GB in use - now 96GB!

    Monday, December 18, 2017 8:30 PM
  • Hi laurin1,

    >So I set it to 64, as I said, and now the number of copies are increasing, but why? What arbitrary limitation is keeping it from using 64 anyway?

    I have seen the scenario before, the MaxShadowCopies is set large.

    But the value "Maximum Shadow Copy Storage space: 48.828 GB (2%)" sometime not enough, so that limit you keep more ShadowCopies.

    We could use Vssadmin resize shadowstorage to increase.

    For example:

    vssadmin resize shadowstorage /for=c /on=c /maxsize=unbounded

    Best Regards,

    Mary


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Tuesday, December 19, 2017 3:01 AM
    Moderator

  • Hi,

    Just checking in to see if the information provided was helpful. Please let us know if you would like further assistance.

    Best Regards,

    Mary


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, December 20, 2017 9:27 AM
    Moderator
  • So I set it to 64, as I said, and now the number of copies are increasing, but why? What arbitrary limitation is keeping it from using 64 anyway?

    Also, and this is very strange, the usage on these jumped way up (not proportionally).

    • Server 2008 R2 Service Pack 1
    • 6 copies - now has 16
    • 50GB allocated
    • 8GB in use - now is 50GB!

    • Server 2012 R2
    • 10 copies - now has twice that
    • 100GB is allocated
    • 10GB in use - now 96GB!

    Well, this was only a temporary fix for one of these machines (the other is still working). Status as of this morning (no idea when it stopped, I only check these once a quarter):

    • Server 2008 R2 Service Pack 1
    • 3 copies
    • 50GB allocated
    • 3GB in use


    Tuesday, March 13, 2018 3:37 PM
  • Weird, it's like I touch it and it starts working, as today it's back up to:

    • Server 2008 R2 Service Pack 1
    • 10 copies
    • 50GB allocated
    • 10GB in use

    Friday, March 16, 2018 5:32 PM
  • Today:

    • Server 2008 R2 Service Pack 1
    • 3 copies
    • 50GB allocated
    • 4 GB in use

    Tuesday, March 20, 2018 3:39 PM
  • Today:

    • Server 2008 R2 Service Pack 1
    • 3 copies
    • 50GB allocated
    • 4 GB in use

    Hi Laurin,

    did you solve this problem?
    I also have it on two different Server 2016 with exaclty the same symptoms.

    We're using deduplication in combination with stroage replica.

    Automatic defragmentation is disabled, as defragmentation could also cause volume shadow copies being deleted.

    Maybe it's an I/O-issue as read here:
    https://social.technet.microsoft.com/Forums/en-US/fd0096ad-9fdd-41a6-bfd2-78bbe4c259aa/shadow-copies-issues-with-windows-server-2012-r2-deduplication-and-defragmentation?forum=winserverfiles

    cheers,
    Roman

    Thursday, June 21, 2018 10:48 AM
  • On 1 server, the changes in this thread "seemed" to help (I suspect the issues just went away on their own, somehow, actually), but on the primary server that I've had this problem with for a long time now, no. Nothing I've tried helps. This server has performance issues due to being overloaded (including DFS), so we suspect that is the problem (as your link suggests as well), but until we can offload some of those services, we don't know for sure. Anything you find that is helpful is appreciated.
    Thursday, June 21, 2018 12:06 PM