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DPM 2012 SP1 cannot shrink voloume after data deleted RRS feed

  • Question

  • Hi,

    We have DPM 2012 SP1 on Windows 2012

    We have one protection group with 1 TB data and 1 day retention , and we removed some folders due to space from the source location and now there is 250 GB free space.

    Now when I try to Shrink, it’s not allowing to do the shrink.

    Error : Based on the expected data churn of the specified retention range the recovery point volume cannot be shrunk (ID 32071)

     

    I downloaded the script shrink-diskpart.zip from http://social.technet.microsoft.com/Forums/en-US/04988a62-94ef-491e-b073-c16baed49619/how-to-delete-the-old-replica-old-backup-from-disk-in-dpm-2010

    after running the shrink-dispart.ps1 error is :  Not enough recovery points available as set by current retention policy. Shrink is not recommended on this volume

    So , My query is

    1. How to recover\shrink this free space immediately

    2. How much time\days DPM will keep this data in Retention period,

    Saturday, September 7, 2013 12:19 PM

Answers

  • Hi,

    It appears that what you want to do is shrink the Replica volume. DPM does not give you the option to shrink the Replica volume.  Only the recovery point volume can be shrunk and looking at your screen shot, it's only 5GB. 

    The reason why shrinking the Replica is not supported is because when it is shrunk, all the file data that was deleted at one point that resided at the end of the volume - or gets overwritten by moving active files around needs to get copied to the recovery point volume. So you potentially are just trading free space on replica, to new used space on recover point volume.  If recovery point volume is not large enough to accommodate the copy-on-write during the shrink, you can end loosing all shadow copies.   If you don't care about the previous recovery point, then just delete the data source from protection, delete the replica, and re-protect the smaller amount of data.  

    If you want to take a chance on shrinking the replica because you don't want to re-copy the 177gb of data again, then you can use diskpart.exe and manually select the replica volume and try to shrink it.  Add more space to the recovery pointy volume first.  You can try re-shrinking recovery point volume after shrinking the replica.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.


    Saturday, September 7, 2013 4:36 PM
    Moderator

All replies

  • Hi,

    It appears that what you want to do is shrink the Replica volume. DPM does not give you the option to shrink the Replica volume.  Only the recovery point volume can be shrunk and looking at your screen shot, it's only 5GB. 

    The reason why shrinking the Replica is not supported is because when it is shrunk, all the file data that was deleted at one point that resided at the end of the volume - or gets overwritten by moving active files around needs to get copied to the recovery point volume. So you potentially are just trading free space on replica, to new used space on recover point volume.  If recovery point volume is not large enough to accommodate the copy-on-write during the shrink, you can end loosing all shadow copies.   If you don't care about the previous recovery point, then just delete the data source from protection, delete the replica, and re-protect the smaller amount of data.  

    If you want to take a chance on shrinking the replica because you don't want to re-copy the 177gb of data again, then you can use diskpart.exe and manually select the replica volume and try to shrink it.  Add more space to the recovery pointy volume first.  You can try re-shrinking recovery point volume after shrinking the replica.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.


    Saturday, September 7, 2013 4:36 PM
    Moderator
  • you mean we can Grow but can not shrink the volume size.

    Is there any other solution for shrink.

    Friday, September 13, 2013 1:52 PM
  • Q1) You mean we can Grow but can not shrink the volume size.
    A1) Replica volume cannot be shrunk VIA DPM console, only recovery point volume. 

    Q2) Is there any other solution for shrink.
    A2)  As noted in my previous response, you can use diskpart.exe (or Windows disk Management) to manually shrink the replica volume assuming you understand the risks.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Friday, September 13, 2013 6:32 PM
    Moderator
  • hi,

    this script is not my solution.

    Recovery point volume is 374 GB and 8.19 Gb used. There is 360 GB free space in recovery points volume but still I can not shrink.

    Do you have any advice?

    Here is the result.

    Replica volume: 333.27 GB allocated, 275.81 GB used : Recovery point volume: 374.56 GB allocated, 8.19 GB used

    Not enough recovery points avalailable as set by current retention policy. Shrink is not recommended on this volume

    

    Wednesday, October 28, 2015 8:39 AM
  • Hi,

    For that condition you have three options.

    A) wait until you have more recovery points as per the retention goals.

    B) reduce the retention period and retry the script.

    C) run diskpart.exe manually an shrink the recovery point volume.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, October 28, 2015 3:17 PM
    Moderator
  • Good Gawd... that's awful.  I can't imagine someone designing a system like this on purpose.  God will punish you for this :)
    Wednesday, December 7, 2016 10:58 AM