Tape Compression . . - Veritas Backup Exec

This is a discussion on Tape Compression . . - Veritas Backup Exec ; Hi all, We are running bent 7.5 on a hp netserver. Using a HP DDS4 20/40 for backup. I know not to expext much out of compression but we just hit the 20 gig mark on our backups and as ...

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Thread: Tape Compression . .

  1. Tape Compression . .


    Hi all,
    We are running bent 7.5 on a hp netserver.
    Using a HP DDS4 20/40 for backup.

    I know not to expext much out of compression but we just hit the 20 gig
    mark on our backups and as far as I can tell, I am
    only gaining about 500 meg with it. This just doesn't seem
    right.

    Are there any good tweaks for the block and buffer sizes
    on the tape drive settings that may open this up a bit for me?

    Thanks

    Aaron

  2. Re: Tape Compression . . 8.5 not 7.5


    Sorry that is version 8.5

    "auser" wrote:
    >
    >Hi all,
    > We are running bent 7.5 on a hp netserver.
    > Using a HP DDS4 20/40 for backup.
    >
    > I know not to expext much out of compression but we just hit the 20 gig
    >mark on our backups and as far as I can tell, I am
    >only gaining about 500 meg with it. This just doesn't seem
    >right.
    >
    >Are there any good tweaks for the block and buffer sizes
    >on the tape drive settings that may open this up a bit for me?
    >
    >Thanks
    >
    >Aaron



  3. Re: Tape Compression . .


    Hardware or software compression?

    If hardware, verify from Devices/Properties that "enable hardware compression"
    is checked.

    If software, what does BackupExec report as the compression ratio at the
    end of each job step?

    "auser" wrote:
    >
    >Hi all,
    > We are running bent 7.5 on a hp netserver.
    > Using a HP DDS4 20/40 for backup.
    >
    > I know not to expext much out of compression but we just hit the 20 gig
    >mark on our backups and as far as I can tell, I am
    >only gaining about 500 meg with it. This just doesn't seem
    >right.
    >
    >Are there any good tweaks for the block and buffer sizes
    >on the tape drive settings that may open this up a bit for me?
    >
    >Thanks
    >
    >Aaron



  4. Re: Tape Compression . .


    Using hardware, and yes it is checked as enabled.
    Both block and buffer size are set to 32k

    Is it worthwhile trying to run it with software
    compression.. I have always avoided going that route.

    Aaron

    "Ken Putnam" wrote:
    >
    >Hardware or software compression?
    >
    >If hardware, verify from Devices/Properties that "enable hardware compression"
    >is checked.
    >
    >If software, what does BackupExec report as the compression ratio at the
    >end of each job step?
    >
    >"auser" wrote:
    >>
    >>Hi all,
    >> We are running bent 7.5 on a hp netserver.
    >> Using a HP DDS4 20/40 for backup.
    >>
    >> I know not to expext much out of compression but we just hit the 20 gig
    >>mark on our backups and as far as I can tell, I am
    >>only gaining about 500 meg with it. This just doesn't seem
    >>right.
    >>
    >>Are there any good tweaks for the block and buffer sizes
    >>on the tape drive settings that may open this up a bit for me?
    >>
    >>Thanks
    >>
    >>Aaron

    >



  5. Re: Tape Compression . .


    Should be no problem.

    In the old 286/386 days, software compression had so much overhead that it
    could literally double the time it took a job to run (as compared to hardware
    compression) with PII or newer processors and plenty of RAM, I've not noticed
    any diffence in throughput.

    Also. I once got burned by a firware upgrade causing tapes not to be read
    when using hardware compression, (tho I'm told that this really shouldn't
    be a problem now-a-days)
    "auser" wrote:
    >
    >Using hardware, and yes it is checked as enabled.
    >Both block and buffer size are set to 32k
    >
    >Is it worthwhile trying to run it with software
    >compression.. I have always avoided going that route.
    >
    >Aaron
    >
    >"Ken Putnam" wrote:
    >>
    >>Hardware or software compression?
    >>
    >>If hardware, verify from Devices/Properties that "enable hardware compression"
    >>is checked.
    >>
    >>If software, what does BackupExec report as the compression ratio at the
    >>end of each job step?
    >>
    >>"auser" wrote:
    >>>
    >>>Hi all,
    >>> We are running bent 7.5 on a hp netserver.
    >>> Using a HP DDS4 20/40 for backup.
    >>>
    >>> I know not to expext much out of compression but we just hit the 20 gig
    >>>mark on our backups and as far as I can tell, I am
    >>>only gaining about 500 meg with it. This just doesn't seem
    >>>right.
    >>>
    >>>Are there any good tweaks for the block and buffer sizes
    >>>on the tape drive settings that may open this up a bit for me?
    >>>
    >>>Thanks
    >>>
    >>>Aaron

    >>

    >



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