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DFSR and error 4502 stopping replication

    Question

  • I have two servers running Server 2008 and DFS-R with three replication groups. Periodically replication will stop and a backlog will start to grow on one or more replication groups and error 4502 is logged:

    The DFS Replication service encountered errors replicating one or more files because adequate free space was not available on volume Z:. This volume contains the replicated folder, the staging folder, or both. Please make sure that enough free space is available on this volume for replication to proceed. The service will retry replication periodically.

    We are using the built-in quota manger, though there is no quota on any of the dfsrprivate folders and there is plenty of free space on the volume. Also, in Server 2008 the dfsprivate folder in the replicated folder is just a link to the actual folder under 'System Volume Information', so there is absolutly no chance that there is a quota on that folder.
    Any ideas on why this issue keeps comming up?

    Friday, April 3, 2009 7:50 PM

Answers

  • Hi,

     

    As far as I know, DFS-R has been designed to be robust and continue replicating the other folders when it encounters problems. In this case, to prevent this error 4502 from occurring, if possible, would you please refer to the best practice to implanting quota on the DFS namespace share folder?

     

    Distributed File System Replication: Frequently Asked Questions

    http://technet.microsoft.com/en-us/library/cc773238.aspx

     

    Thanks for the co-operation and hope it helps.


    This posting is provided "AS IS" with no warranties, and confers no rights.
    • Marked as answer by David Shen Thursday, April 9, 2009 2:36 AM
    Wednesday, April 8, 2009 9:19 AM
  • Shadow copies is not enabled and there is no Quota Management enabled on the drive.

    I think I somewhat have figured out what has happened. Since we are also using DFS-Namespaces, some users may have connected to one server and added files to a share while other users connected to the same share on the other server and added files. Since a few shares are near their quota limit, Server A couldnt copy the new files to Server B because it was at quota. This behavior is outlined here: http://technet.microsoft.com/en-us/library/cc773238.aspx

    You must use hard quotas with caution. It is possible for individual members of a replication group to stay within a quota before replication, but exceed it when files are replicated. For example, if a user copies a 10 megabyte (MB) file onto server A (which is then at the hard limit) and another user copies a 5 MB file onto server B, when the next replication occurs, both servers will exceed the quota by 5 megabytes. This can cause DFS Replication to continually retry replicating the files, causing holes in the version vector and possible performance problems.

    The thing I still find confusing is why an error in replicating one subfolder in the replication group causes the replication to cease for the entire replication group. It would be nice if DFS-R was robust enough to continue syncing all the files it could instead of just giving up and letting a backlog grow because one folder is having issues. It looks like we just won't be able to use Namespaces anymore because we have hard quotas on all shares.
    • Marked as answer by David Shen Thursday, April 9, 2009 2:36 AM
    Tuesday, April 7, 2009 12:00 PM

All replies

  • Do you have shadow copies enabled?  That could be the problem.  It was for me.

    You can reduce the space available for copies, or disable shadow copies.  You can get to the properties page for shadow copies by right clicking the drive icon in explorer and select "Configure Shadow Copies".
    • Proposed as answer by Easoneric Wednesday, January 28, 2015 4:05 AM
    Sunday, April 5, 2009 10:20 PM
  • Hello,

     

    Based on the description, my understanding the issue is that:

     

    You have configured DFSR replication between two more servers. You might have enabled the Disk quota on the volume where have DFSR Staging Folder and Replicated folders. And you have viewed the bellow error event in the DFSR event log on the problem server. Actually, you have enough free space in the volume Z where we have DFS Replicated folder and Staging area. However, you are still getting the following error message 4502 which states that it has not enough free space on the problem server.

     

    Event Type: Warning

    Event Source: DFSR

    Event Category: None

    Event ID: 4502

    User: N/A

    Computer: Server Name

    Description:

     

    The DFS Replication service encountered errors replicating one or more files because adequate free space was not available on volume Z:. This volume contains the replicated folder, the staging folder, or both. Please make sure that enough free space is available on this volume for replication to proceed. The service will retry replication periodically.

     

    If I have misunderstanding, please feel free to let me know.

     

    Possible CAUSE:

    =================

     

    Disk Quota is enabled on the volume Z where has DFS-R Staging Folder and Replicated folders. Also Quota Limit is less than Staging area size.

     

    Under this circumstance, Disk Quota will limit the size of the staging folder even though we have enough free space in this volume, which will cause DFSR replication error 4502.

     

    Please follow the bellow steps to check whether Disk Quota is enabled.

     

    1.   Open My Computer and Right Click and select Properties of the specific volume.

    2.   Select the tab Quota. Here you can see whether Quota Management is enabled or not.

     

    Resolution:

    ============

     

    To resolve this issue, we may need to disable Disk Quota or increase the Quota limit (larger than Staging area size) on the volume where has DFSR staging folders.

     

    Please follow the following steps to disabling Quota Management.

     

    1. Open My Computer and Right Click and select Properties of the specific volume.

     

    2. Select the Tab Quota. Clear the Check Box "Enable Quota Management".

     

    After disabling the Disk Quota, we may need to restart the DFSR Service on the problem server.

     

    Hope this can be helpful.


    This posting is provided "AS IS" with no warranties, and confers no rights.
    • Proposed as answer by David Shen Tuesday, April 7, 2009 9:50 AM
    • Unproposed as answer by David Shen Tuesday, April 7, 2009 9:50 AM
    Tuesday, April 7, 2009 9:44 AM
  • Shadow copies is not enabled and there is no Quota Management enabled on the drive.

    I think I somewhat have figured out what has happened. Since we are also using DFS-Namespaces, some users may have connected to one server and added files to a share while other users connected to the same share on the other server and added files. Since a few shares are near their quota limit, Server A couldnt copy the new files to Server B because it was at quota. This behavior is outlined here: http://technet.microsoft.com/en-us/library/cc773238.aspx

    You must use hard quotas with caution. It is possible for individual members of a replication group to stay within a quota before replication, but exceed it when files are replicated. For example, if a user copies a 10 megabyte (MB) file onto server A (which is then at the hard limit) and another user copies a 5 MB file onto server B, when the next replication occurs, both servers will exceed the quota by 5 megabytes. This can cause DFS Replication to continually retry replicating the files, causing holes in the version vector and possible performance problems.

    The thing I still find confusing is why an error in replicating one subfolder in the replication group causes the replication to cease for the entire replication group. It would be nice if DFS-R was robust enough to continue syncing all the files it could instead of just giving up and letting a backlog grow because one folder is having issues. It looks like we just won't be able to use Namespaces anymore because we have hard quotas on all shares.
    • Marked as answer by David Shen Thursday, April 9, 2009 2:36 AM
    Tuesday, April 7, 2009 12:00 PM
  • Hi,

     

    As far as I know, DFS-R has been designed to be robust and continue replicating the other folders when it encounters problems. In this case, to prevent this error 4502 from occurring, if possible, would you please refer to the best practice to implanting quota on the DFS namespace share folder?

     

    Distributed File System Replication: Frequently Asked Questions

    http://technet.microsoft.com/en-us/library/cc773238.aspx

     

    Thanks for the co-operation and hope it helps.


    This posting is provided "AS IS" with no warranties, and confers no rights.
    • Marked as answer by David Shen Thursday, April 9, 2009 2:36 AM
    Wednesday, April 8, 2009 9:19 AM