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Compression and dedup

Discussion in 'Backup / Archive Discussion' started by StiffBoard, Jan 9, 2017.

  1. StiffBoard

    StiffBoard Newcomer

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    Hi, if I'm using COMPRESSION Yes (FORCE) ON in my client option set, will compression always be on even if I use COMPRESSION NO in dsm.opt? Nodes have the setting COMPRESSION CLIENT

    I'm getting a lot of Object increased in size during compression... and then Sending of object failed on backup clients. Not sure how to go about that...

    What is the recommendation for dedup and compression, one or the other or can they work together in a good way? Any general guidelines here?
     
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  3. marclant

    marclant ADSM.ORG Moderator

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    Yes.
    If using client-side dedup, you can use client-side compression without issues. If you are still getting data grows, you can use COMPRESSALWAYS NO

    If not using client-side dedup, don't use client-side compression because the server will not find duplicates in compressed data. Send the data uncompressed and the server will compress it after it's deduplicated.

    source: https://www.ibm.com/developerworks/...Tivoli Storage Manager/page/Deduplication FAQ
     
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  4. StiffBoard

    StiffBoard Newcomer

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    Hi, thanks for the answer. So, if my nodes have the setting Deduplication Serveronly I shouldn't be using Compression? Even if I do, dedup of bit patterns will still be able to dedup some data?

    If I remove the Force flag on Compression Yes in clientoptset, will COMPRESSION NO i dsm.opt work then?

    Will COMPRESSALWAYS NO in dsm.opt skip compression even if Force flag is on?

    Will check that Dedup FAQ, haven't found that one before, thanks.
     
  5. marclant

    marclant ADSM.ORG Moderator

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    Exactly.
    Not with server-side dedup, but yes will client-side dedup.
    Correct. Or if you are not doing client-side dedup anywhere, I'd change the client option to COMPRESS NO, to make sure no clients that are doing server-side dedup can use compression.
     
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  6. StiffBoard

    StiffBoard Newcomer

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    Brilliant, thanks very much
     

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