Data Deduplication, Defrag & DPM 2012 R2 Churn RRS feed

  • Question

  • We have a protected 2012 R2 server that has Data Deduplication enabled. DPM tried to create a recovery point and ran out of disk space. When I check to see what happened, the job had transferred over 43GB of data.  This is way outside of the norm for this protection group.  Upon investigation I found that a scheduled weekly defrag had run.  I assume this to be the source of the churn.  Can anyone provide an guidance on the interaction of the these processes?  The scheduled defrag was enabled by default.  I assume we'll need to disable this?  I have never defragged my VM's as it would cause massive churn for the VM backup's in DPM.  But this was not a VM backup, just a backup of files on a deduplicated volume.



    Monday, September 22, 2014 1:57 PM

All replies

  • It's a bit confusing...
    To specify the actual setup and how you backup the Server would be nice.

    They're are VMs and a Hyper-V machine with enabled dedup but how exactly is mysterious.

    The dedup schedule can interfere because of lack of ressources with the underlaying "hard drive" System...of course. But I couldn't seen this very often. Maybe a mix about less IO Performance + less RAM?

    Specifiy your Environment to sharpen up the possibilities. ;)

    Monday, September 22, 2014 9:58 PM
  • Thanks for the reply.  It's pretty simple really.  I have a 2012 R2 file server with data deduplication enabled on one of the volumes.  There was a scheduled defrag that ran on the volume and appears to have caused massive churn for the DPM recovery point.  Question is if this is unique to data deduplication and DPM?  The same problem occurs when you defrag a VM that's being backed up by DPM.  That's why we don't defrag our VHDs.  Normal file servers without data deduplication do not exhibit this behavior.  The scheduled defrag was set by default and I'm assuming needs to be disabled.  I'm just looking for guidance on why this is an issue. 
    Tuesday, September 23, 2014 1:48 PM
  • I can see a defrag task on a couple of fileservers as well.
    But the Task starts and change to completed in around 3 seconds.
    It looks like a common Background task without a frequent schedule.

    called "ScheduledDefrag" - TS Library - Microsoft - Windows - defrag ... directly under deduplication

    some of these fileservers are virtual some are physical installations.

    Wednesday, September 24, 2014 7:36 AM