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DPM Error RRS feed

  • Question

  • Hello,

    We are protecting our clustered file server with DPM. Everything works fine but some times approximately once per month we getting error for synchronization job:

    A journal wrap error has occurred on the change journal, and therefore DPM is unable to track any more changes or may have missed some changes for the data source E:\ on server1.server2.domain.com (ID 30117 Details: Internal error code: 0x809909D1). After that my replica becomes inconsistent and long verification process should be started.

    Have found some articles i.e. Link1  about, but it is not still fully clear for me. Can someone explain in little bit more details what does this error mean and what can be the reason.

    Thank you in advance.



    Monday, March 23, 2015 1:03 PM

Answers

  • Hi,

    DPM uses the NTFS USN change journal to help locate files that have changed since the last synchronization or recovery point.  The USN journal is a cyclic file, meaning that older records are overwritten as needed based on the USN journal file size. It seems a process is changing something about files that USN tracks that is causing the USN to wrap, and once that occurs, you will get the error in DPM.

    Everything you ever wanted to know about the NTFS USN journal and were afraid to ask can be read about here and here.

    Happy reading... 


    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.

    Monday, March 23, 2015 8:51 PM
    Moderator

All replies

  • Hi,

    The default USN journal size is 300MB and in most cases that is large enough to accommodate tracking an active volume for awhile before wrapping.  You can easily increase the USN journal using the Modify disk allocation wizard.  You can make it larger but not smaller using the wizard, so perhaps just double the size to 600MB and that should do it.

     


    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.

    Monday, March 23, 2015 4:40 PM
    Moderator
  • Hello Mike,

    Thanks for your response. I already changed allocated space for change journal  when the last time error has occurred and hope now it helps.

    But i still fully don't understand what this error means and what can be the reason for this event.

    Thank you

    Monday, March 23, 2015 7:32 PM
  • Hi,

    DPM uses the NTFS USN change journal to help locate files that have changed since the last synchronization or recovery point.  The USN journal is a cyclic file, meaning that older records are overwritten as needed based on the USN journal file size. It seems a process is changing something about files that USN tracks that is causing the USN to wrap, and once that occurs, you will get the error in DPM.

    Everything you ever wanted to know about the NTFS USN journal and were afraid to ask can be read about here and here.

    Happy reading... 


    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.

    Monday, March 23, 2015 8:51 PM
    Moderator

  • Thanks alot, it's more than clear now :)
    Monday, March 23, 2015 9:00 PM
  • Unfortunately i increased allocated space for change journal a but still getting same error and cant find the reason. :(. 


    Wednesday, March 25, 2015 8:35 AM
  • You have an offending application (most likely anti-virus) that is either touching lots of files, or is updating a single file or set of files constantly which is causing the USN journal to wrap between DPM Synchronization jobs. 

     To see what files may be causing the USN journal to wrap, perform the following steps,

    1) Download the DPM 2010 diagnostic and install it on the protected sever.

    http://www.microsoft.com/en-us/download/details.aspx?id=9462

    2) After it's installed from an administrative command prompt cd to: C:\Windows\MPSReports\DPM\bin

    3) Run dumpusn.exe X: -e -o C:\temp\usnlog.txt (Where X: is the protected volume drive letter)

    4) Press CTRL+C to stop it otherwise the file will be too large to open in notepad.

    5) Open the file and see if there is a common set of files that are constantly being updated.  If you find some, you can use resource monitor to see what application or process that is responsible.  Update or un-install that application.


    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, March 25, 2015 3:04 PM
    Moderator
  • Thanks one more time. I will try to follow your instructions.
    Wednesday, March 25, 2015 9:55 PM