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hetfield_86's avatar
hetfield_86
Level 5
14 years ago

About hardware compression...

 Hello everybody

I have this situation:

when I backup a linux or windows directory to tape, this device compress it well. But on a Backup Policy, with a Duplicate Template to tape, the directory doesn't go to tape as compressed and appears a 1:1 Compression Ratio in this device.

 

What could be cause of this behavior??

 

Thanks for helping

12.x and Earlier
Backing Up
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Backup Exec
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  • CraigV's avatar
    CraigV
    14 years ago

    Hi Hetfield,

     

    If your data is already compressed, it won't compress again.

    It's the same as trying to compress a zip file...same concept.

    Seeing as how it was compressed once to tape, that's all you will get when duplicating.

     

    Craig

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  • CraigV's avatar
    CraigV
    Moderator
    14 years ago

    Hi Hetfield,

     

    If your data is already compressed, it won't compress again.

    It's the same as trying to compress a zip file...same concept.

    Seeing as how it was compressed once to tape, that's all you will get when duplicating.

     

    Craig

  • hetfield_86's avatar
    hetfield_86
    Level 5
    14 years ago

    Hi Craig look I save the directory to a device and there I don't compresse it 'cause that device doesn't support compression, but when I gonna do it with same directory to tape, it appears as compressed.

     

    now in a policy of backup full(to D2D) and duplication (to Tape), when it goes to tape, it doesn't go as compressed.

     

    Do you understand me???

     

    Thanks for helping

  • pkh's avatar
    pkh
    Moderator
    14 years ago

    You should look at the job logs for the job that backed up your data to disk as well as the duplicate to tape job.  They should tell you want compression is used, hardware, software or none.

    Although your disk device may not support compression, you can still use software compression to compress the data.  Then like what Craig said, this data would not be compressed further.

    I backup some of my databases to disk and then duplicate them to tape.  I use software compression for my backup job which compresses 15GB of data to 2GB.  Even though I specify hardware compression for my duplicate job, 2GB of data got written to tape and I too get 1:1 compression.