using compression for image backups

Discussion in 'backup, imaging & disk mgmt' started by beethoven, Jun 4, 2013.

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  1. beethoven

    beethoven Registered Member

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    Just wondering if using compression when making images has any effect on the reliability later on? If so, is there any difference in this respect between standard or high compression? Finally adding encryption - does that have any issues on reliability later on?
     
  2. TheRollbackFrog

    TheRollbackFrog Registered Member

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    BT, both compression and encryption are based on well tested mathematical lossless algorithms that are fully retrievable as far as data is concerned. They should do nothing to the eventual reliability of the data involved.

    Of course, flakey RAM, flakey HDDs, flakey electrical paths and flakey memories (ours, maybe, as far as remembering encryption passwords are concerned) within your system can and will cause problems (some soft, some hard) with any kind of data... compressed, encrypted or otherwise.

    Edit: only difference between "standard" and "high" compression is the algorithm in use. HIGH compression compresses the data a bit more but needs much more CPU time to do it... probably not worth it unless you're really short of storage space.
     
    Last edited: Jun 4, 2013
  3. beethoven

    beethoven Registered Member

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    Thankyou - Rollbackfrog - much appreciated.
     
  4. Solarlynx

    Solarlynx Registered Member

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    I would suppose that the more compressed image the less it's tolerant if there's some faulty bytes in the HD where the image is allocated. Just my supposition.
     
  5. MarcP

    MarcP Registered Member

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    Compression or not, one faulty byte will make the whole image fail integrity check.
     
  6. Peter2150

    Peter2150 Global Moderator

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    I've never had any issues with old images.

    I know the folks at Storagecraft, do recommend occasionally verifying images to be sure they don't change. My mentor there fussed at me for deleing the md5 files, as you need them to compare verify's to see that they didn't change.

    All that said, even my oldest images have been fine.

    Pete
     
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