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How Changing the File Structure will affect DPM backup

    Question

  • We have a large file server that is protected by DPM2010.  The protected data is split between two folders.

    E:\Folder1 (2TB of data)

    E:\Folder2 (2TB of data)

    I need to combine the data from Folder2 into Folder1.  This is quick enough.  A simple cut and paste gets the data into folder no problem.

    1. Once this change is made, will DPM re-copy over the 2TB of data that is now located in Folder1?

    2. Will DPM duplicate this data on the backup server since the data is located in a new location?

    3. What will DPM do in this scenario?

     

    Thanks,

    Caleb

     

    Monday, November 21, 2011 11:18 PM

Answers

  • Update -

    So I tested this out today.  I'm not sure if there was some miscommunication between Laith and I, but changing the file structure (renaming folders or moving data from one folder to the other) does not require DPM to backup these files all over again, nor does it store the data twice within DPM.  Here is what I did. 

    1. I did a fresh back of a volume with 4GB of data on it.  
    2. After the first Backup:  Replica Volume: 4.09GB Used  Recovery Point Volume 687.31mb used
    3. I then renamed the folders and moved them around within the stucture.
    4. I then performed a "Create a recovery point after syncronizing"
    5. The syncronization and recovery point operation took only 11sec to complete and .13mb of data was transferred.  I pulled this from the Completed jobs section
    6. I then reviewed the Disk Allocation Status again:  Replica Volume: 4.09GB Used  Recovery Point Volume 688.78mb used

    From this test I concluded that DPM simply tracks the changes made to the location and does not need to backup the same data again.  If the data was copied from one location to the other and not moved, DPM would have to backup this data again, but because this was a move/cut&paste operation, only changes the path were made.

    Hopefully this data will help someone else out there. 

    • Marked as answer by Caleb44 Wednesday, February 15, 2012 11:09 PM
    Wednesday, February 15, 2012 11:09 PM

All replies

  • Consider DPM as a normal backup program.

    When you backup a folder then it stays their. Consider the following scenario. If you accedently deleted files in Folder2 and you need to restore it after 3 days. You will go back were the data were backed up and restore it. and if you check Folder2 under the next 2 two days you will see it empty.

     

    What im trying to say here is that When you take backup to Folder2 the data will be kept in DPM untill the retention data will finish.

    So if you will copy the files. DPM will take the end results. that means (Folder1+Folder2x2).

    I had a similar issue with the same amout of data. What i did is that. I informed the users not to work in these folders after 18:00. Scheduled the backup to be run at 18:00. i know that the backup will take around 10 minutes to finish (do sync more often for this task). Copy the folder (so that DPM will not take double backup). Then next day when DPM will run then he will take the backup only for the new folder.

    DPM will delete old data after the retention period is over.

     

    Hope that helps,

    Laith

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    Thursday, December 01, 2011 2:40 PM
  • Thanks for the reply Laith.  I'm not sure if I am following you correctly.  Why did you copy the files?  If I copy the files that means that I will eat up an additional 2TB of data that is not needed. 

    Another question that I have would be, how does DPM handle the data if Folder2 is renamed to Folder3.  Would it make an entirely new copy of Folder3?

    Thursday, December 01, 2011 4:46 PM
  • Sorry i meant move the folder not copy it.

    If you will rename the folder DPM will keep the backup for Folder2 and will take backup to Folder3 as a new folder.

     

    Hope that help,

    Laith

    _________________________________________________

    If you found this helpful please mark it as an Answer.

     

     

    Thursday, December 01, 2011 7:38 PM
  • I guess I'm still a little confused.  Can you answer these two questions to help clear things up?
    1. Once Folder2 has been moved into Folder1, will DPM re-copy over the 2TB of data that is now located in Folder1?
    2. Will DPM duplicate this data on the backup server since the data is located in a new location?
    Wednesday, December 07, 2011 5:40 PM
  • 1. DPM will take a new copy for the 2TB copied.

    2. As i said its not duplicating. Its the same data but in a different place. So yes it will take a new backup.

     

    To make it easier for you think of it like the following. You have Folder1 and Folder2. You decided to delete folder1 and add it to Folder2. Then after some days you decided noticed that you need Folder1 so you bring it from old backup.

     

    And then after few days you decided to bring back Folder2 as folder1 and folder2 then you bring back the backup after merging the both.

     

    Backup programs are unware of the data. If you have a 100 duplicated files then it will take them all. What ever file structure you will have DPM will take it.


    Hope that help,

    Laith

    _________________________________________________

    If you found this helpful please mark it as an Answer.

    • Edited by Laith_IT Monday, December 12, 2011 11:57 AM
    • Marked as answer by Caleb44 Monday, December 12, 2011 5:14 PM
    • Unmarked as answer by Caleb44 Wednesday, February 15, 2012 11:09 PM
    Monday, December 12, 2011 11:57 AM
  • That's disappointing to hear.  I would have thought DPM would have been able to track a simple change to the path of the data.  Thanks Laith.
    Monday, December 12, 2011 5:14 PM
  • Update -

    So I tested this out today.  I'm not sure if there was some miscommunication between Laith and I, but changing the file structure (renaming folders or moving data from one folder to the other) does not require DPM to backup these files all over again, nor does it store the data twice within DPM.  Here is what I did. 

    1. I did a fresh back of a volume with 4GB of data on it.  
    2. After the first Backup:  Replica Volume: 4.09GB Used  Recovery Point Volume 687.31mb used
    3. I then renamed the folders and moved them around within the stucture.
    4. I then performed a "Create a recovery point after syncronizing"
    5. The syncronization and recovery point operation took only 11sec to complete and .13mb of data was transferred.  I pulled this from the Completed jobs section
    6. I then reviewed the Disk Allocation Status again:  Replica Volume: 4.09GB Used  Recovery Point Volume 688.78mb used

    From this test I concluded that DPM simply tracks the changes made to the location and does not need to backup the same data again.  If the data was copied from one location to the other and not moved, DPM would have to backup this data again, but because this was a move/cut&paste operation, only changes the path were made.

    Hopefully this data will help someone else out there. 

    • Marked as answer by Caleb44 Wednesday, February 15, 2012 11:09 PM
    Wednesday, February 15, 2012 11:09 PM