Alternate Data Path and NOT Global Dedupe

Last post 05-29-2019, 6:59 PM by Wwong. 3 replies.
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  • Alternate Data Path and NOT Global Dedupe
    Posted: 05-23-2019, 12:21 PM

    Hi all,

    Similar to the following forum post,, I have a situation where I cannot add a new MA and library to a Storage policy copy. However, in this case, it does not involve a Global Dedupe policy - there is no Global Dedupe at this site.

    I am able to add the MA and library to a non-dedupe policy.

    Incidentally, each of the SP copies do not show the DDB Information section in the Deduplication tab when looking at the copy properties. I can verify from the Deduplication Engines that the policy/copy does use dedupe and can see the path to the DDB itself.

    Any ideas?


  • Re: Alternate Data Path and NOT Global Dedupe
    Posted: 05-24-2019, 10:35 PM

    Hi originaljamster 

    In relation to Global Deduplication Policy or a normal Deduplication Policy (depending on Service Pack), Commvault has removed the capability of adding additional Data Path, mainly because you will be spreading the Deduped data across different Disk Library (and potentially different backend storage). 

    The above is not best practice and would not be recommended, because once you add another Disk Library, the associated Mount Path in the Disk Library will be linked to the DDB. Meaning you will have multiple-point of failure, and in the unlikely scenario where you lose one Disk Library (pretty much all your backup might not be restoreable - because the required block might exist in the offline library). 

    Rather then adding more Disk Library to complicate the setup, it would be recommended to add more Mount Path to the existing Library (recommend to come from same storage) or expand the backend storage (expand the LUN/CIFS/NFS at the storeage level). 

    Hopefully that helps 



  • Re: Alternate Data Path and NOT Global Dedupe
    Posted: 05-29-2019, 12:38 PM

    Hi Winston,


    Thanks for your update. I guess I've been guilty of just trying to resolve the immediate issue and not looking at the bigger picture. In this case, the need to is move from one MA and associated disk lib to a separate MA and disk library. Would a Mount Path move be the best option which would take care of dedupe etc?


    Thanks, Jamie

  • Re: Alternate Data Path and NOT Global Dedupe
    Posted: 05-29-2019, 6:59 PM

    Hi Jamie

    If you are considering moving the data, you have the following option:

    • Move Mount Path to another available volume on the MA (can be the same MA or another MA, it all depends on whether you can provision new volume to be mounted on the MA)
      • Note - you do not need to add the new volume into Commvault, you just need to choose the destination volume when doing Move Mount Path.
    • Create a new Disk Library and DDB, and do an Aux Copy from the Primary Copy to the Secondary. Once Aux copy is complete, the promote the Secondary Copy as Primary 
    Both options will require a bit of planning in regards to migration of your protection data. 
    Kind Regards
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