tape

[hike]

2008/9/11 Miner, Jonathan W (US SSA) <jonathan.w.miner at baesystems.com>

> You need to specify the "no rewind" device... /dev/nst0
>
> You will need to seek to the end of the tape before writing new data to the
> tape.  Look at the "st" and "mt" man pages.
>
> I don't know any way to know how much free space is on a tape; it's
> complicated due to compression since you don't really care how much tape is
> left, but how much data will fit on that tape.... which depends on how well
> the data will compress.
>
>
> -----Original Message-----
> From:   redhat-list-bounces at redhat.com on behalf of ammad shah
> Sent:   Thu 9/11/2008 4:23 PM
> To:     redhat-list at redhat.com
> Cc:
> Subject:        tape
>
> Dear all,
>
> i am trying to backup on tape drive (lto3), but when i save it , it always
> overwrite on previous files. even though i am writing every time a new file.
>
> #tar -cvf /dev/st0  backup-01-09.tar.gz
> #tar -tvf /dev/st0
> backup-01-09.tar.gz
> #tar -czvf /dev/st0 backup-02-09.tar.gz
> #tar -tvf /dev/st0
> backup-02-09.tar.gz
>
> Why ?
>
> and how do i know space left on tape drive before backup.  i am using
> single cartridge IBM LTO 3 tape drive.
>
> thanks.
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there is no way to know how much space is left on the tape.
we break the tape backup into volume (1 tape == 1 volume).
we figure out which filesystems go to which volume based on the size of the
filesystems and adjust as needed.
this has worked out very well for us.
and easy!