40/80 GB tapes running out of space at 54GB - Veritas Backup Exec

This is a discussion on 40/80 GB tapes running out of space at 54GB - Veritas Backup Exec ; Our backups were going fine up until last Friday when we had to add more data to our server. Now the backup stops at about 54GB and asks for a new tape. I thought it could backup 80 GB. We ...

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Thread: 40/80 GB tapes running out of space at 54GB

  1. 40/80 GB tapes running out of space at 54GB


    Our backups were going fine up until last Friday when we had to add more data
    to our server. Now the backup stops at about 54GB and asks for a new tape.
    I thought it could backup 80 GB. We are using Back Up Exec 8.6 on a Windows
    NT 4 with software compression, Overwrite Media and Backup Method - Full
    - Backup Files - Reset Archive. Any idea how to make it backup 80 GB? It's
    happening with all the tapes so I don't think it's an "old tape" issue.

    Thanks

  2. Re: 40/80 GB tapes running out of space at 54GB

    80GB capacity is based on 2:1 compression ratio. In the real world, you
    rarely would get that much compression. It all depends on your data set. Try
    using software compression. That way, you can see the compression ratio on
    your backup log (Software compression ratio: x:x). I doubt that you're
    anywhere near 1.5:1 compression.

    "Clifford Law" wrote in message
    news:3ed3bafd$1@hronntp01....
    >
    > Our backups were going fine up until last Friday when we had to add more

    data
    > to our server. Now the backup stops at about 54GB and asks for a new tape.
    > I thought it could backup 80 GB. We are using Back Up Exec 8.6 on a

    Windows
    > NT 4 with software compression, Overwrite Media and Backup Method - Full
    > - Backup Files - Reset Archive. Any idea how to make it backup 80 GB? It's
    > happening with all the tapes so I don't think it's an "old tape" issue.
    >
    > Thanks




  3. Re: 40/80 GB tapes running out of space at 54GB

    On 27 May 2003 15:22:37 -0400, Clifford Law wrote:

    > Our backups were going fine up until last Friday when we had to add more data
    > to our server. Now the backup stops at about 54GB and asks for a new tape.
    > I thought it could backup 80 GB. We are using Back Up Exec 8.6 on a Windows
    > NT 4 with software compression, Overwrite Media and Backup Method - Full
    > - Backup Files - Reset Archive. Any idea how to make it backup 80 GB? It's
    > happening with all the tapes so I don't think it's an "old tape" issue.


    The tapes have 40 GB capacity, the 80 GB figure comes from using
    compression with an optimistic 2:1 compression ratio (which is fairly
    common for tape manufacturers).

    In practice, the compression ratio depends on what you're backing up.
    We generally see about 1.6:1 here, so that would get 64 GB on a tape.

    --
    Mark Hill
    #include

  4. Re: 40/80 GB tapes running out of space at 54GB


    According to the log our compression rate was 1.3:1. Software compression
    is what we've been using. We'll try hardware compression tonight. Otherwise
    it looks there's nothing else we can do to increase the compression rate...

    Clifford

    "Ron" wrote:
    >80GB capacity is based on 2:1 compression ratio. In the real world, you
    >rarely would get that much compression. It all depends on your data set.

    Try
    >using software compression. That way, you can see the compression ratio

    on
    >your backup log (Software compression ratio: x:x). I doubt that you're
    >anywhere near 1.5:1 compression.
    >
    >"Clifford Law" wrote in message
    >news:3ed3bafd$1@hronntp01....
    >>
    >> Our backups were going fine up until last Friday when we had to add more

    >data
    >> to our server. Now the backup stops at about 54GB and asks for a new tape.
    >> I thought it could backup 80 GB. We are using Back Up Exec 8.6 on a

    >Windows
    >> NT 4 with software compression, Overwrite Media and Backup Method - Full
    >> - Backup Files - Reset Archive. Any idea how to make it backup 80 GB?

    It's
    >> happening with all the tapes so I don't think it's an "old tape" issue.
    >>
    >> Thanks

    >
    >



  5. Re: 40/80 GB tapes running out of space at 54GB

    I don't really like hardware compression. I've had problem restoring
    hardware compressed backup using 2 different tape drives. Backup was made on
    a Compaq tape changer and restore was done on a Seagate single drive (both
    are DDS3 drives). Restore failed with so many errors.

    As I said before, compression rate depends on your data set. Text files
    compresses much better than jpeg files for example. Nothing you can do to
    get better compression rate.

    "Clifford Law" wrote in message
    news:3ed4e7ed$1@hronntp01....
    >
    > According to the log our compression rate was 1.3:1. Software compression
    > is what we've been using. We'll try hardware compression tonight.

    Otherwise
    > it looks there's nothing else we can do to increase the compression

    rate...
    >
    > Clifford
    >




  6. Re: 40/80 GB tapes running out of space at 54GB

    Also, it depends what you are backing up. If you are backing up a MS
    Exchange mailboxes the size of the files can be misleading due to
    compression.


    "Mark Hill" wrote in message
    news:3ed46aa5.2481264734@news.august-systems.co.uk...
    > On 27 May 2003 15:22:37 -0400, Clifford Law wrote:
    >
    > > Our backups were going fine up until last Friday when we had to add more

    data
    > > to our server. Now the backup stops at about 54GB and asks for a new

    tape.
    > > I thought it could backup 80 GB. We are using Back Up Exec 8.6 on a

    Windows
    > > NT 4 with software compression, Overwrite Media and Backup Method - Full
    > > - Backup Files - Reset Archive. Any idea how to make it backup 80 GB?

    It's
    > > happening with all the tapes so I don't think it's an "old tape" issue.

    >
    > The tapes have 40 GB capacity, the 80 GB figure comes from using
    > compression with an optimistic 2:1 compression ratio (which is fairly
    > common for tape manufacturers).
    >
    > In practice, the compression ratio depends on what you're backing up.
    > We generally see about 1.6:1 here, so that would get 64 GB on a tape.
    >
    > --
    > Mark Hill
    > #include




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