Tape not being filled to capacity? - Veritas Backup Exec

This is a discussion on Tape not being filled to capacity? - Veritas Backup Exec ; We are using BE 9 with a NetWare 6 server and a DELL autoloader. In recent months, the full backup job will not complete on 7 tapes and requests another tape, which we cannot give it of course, since the ...

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Thread: Tape not being filled to capacity?

  1. Tape not being filled to capacity?


    We are using BE 9 with a NetWare 6 server and a DELL autoloader. In recent
    months, the full backup job will not complete on 7 tapes and requests another
    tape, which we cannot give it of course, since the autoloader has only 7
    slots. As of today, the space usage reported on the SYS volume by C1 is
    2.85 GB and the usage on VOL is 276.88 GB. There is no NetWare compression
    on either volume. This totals 279.73 GB and at a minimum of 40 GB per tape
    (we use DLT IV's), this is right at the limit of 7 tapes. Also, we don't
    back up all the data on VOL. So, we are suspicious that we are not getting
    all of the capacity possible from our tapes. BE is set to us hardware compression.
    Haven't check the drive yet to see if it is set up correctly, but other
    than that, does anyone have any suggestions? Thanks.

  2. Re: Tape not being filled to capacity?


    I am having a similar problem. I hope someone can respond to this issue. I
    use SDLTs. I could not possibly be getting any compression from what I can
    tell. And besides that I only get 160GB (if that)per tape instead of the
    320GB.


    "Denise" wrote:
    >
    >We are using BE 9 with a NetWare 6 server and a DELL autoloader. In recent
    >months, the full backup job will not complete on 7 tapes and requests another
    >tape, which we cannot give it of course, since the autoloader has only 7
    >slots. As of today, the space usage reported on the SYS volume by C1 is
    >2.85 GB and the usage on VOL is 276.88 GB. There is no NetWare compression
    >on either volume. This totals 279.73 GB and at a minimum of 40 GB per tape
    >(we use DLT IV's), this is right at the limit of 7 tapes. Also, we don't
    >back up all the data on VOL. So, we are suspicious that we are not getting
    >all of the capacity possible from our tapes. BE is set to us hardware compression.
    > Haven't check the drive yet to see if it is set up correctly, but other
    >than that, does anyone have any suggestions? Thanks.



  3. Re: Tape not being filled to capacity?

    Chris
    > I am having a similar problem. I hope someone can respond to this issue. I
    > use SDLTs. I could not possibly be getting any compression from what I can
    > tell. And besides that I only get 160GB (if that)per tape instead of the
    > 320GB.


    Firstly, just a little background:
    When tape manufacturers quote figures for tape capacity, they quote
    both native & the compressed amount (assuming a compression rate of 2:1)
    - for instance yours will be 160/320. The only amount that you can more
    or less guarantee to get on there is the native figure.
    Compression ratios are fairly subjective. The much vaunted 2:1 figure is
    rarely achieved in full (a more realistic average figure is around
    1.6:1) - they mostly depend on whether the data is already compressed on
    disk and what type of data the file contains. Now, if a file is already
    compressed on disk, it can't be compressed any more, and the actual size
    on tape will probably be higher than it is on disk because an extra
    header is written during the compression attempt.

    In your case, is there any compression enabled on the NetWare volume?
    What compression type have you got set in BE (hardware or software)? If
    you change that around, is it still the same problem?
    Have you got backup compressed files as uncompressed set?
    What version & build of BE, version & SP of NW are you using?
    What tape device (make & model) & firmware revision are you using?

    Michael
    --
    "If it jams, force it. If it breaks, you probably
    needed a new one anyway"

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