[plug] TAR & MT

[David Griffiths]

Hi Mike,

>
>I have just had that unfriendly feeling that my backups have not been
>working and someone wants something recovering ... %^(
>
snip

>
>My idea being that I could then use the mt command to step through these
>"tars" to the one I want to recover something. I just tried a mt -f
>/dev/st0 fsf 2 to get to the second tar file and it gives I/O error.
>

The device you probably want to use here is /dev/nst0,
                                 ^
where the n stands for no rewind. Haven't tried the st0 device with mt but
suspect it's just gonna want to rewind after doing what you want.


>How can I verify that I have the three tar files on the tape, using tar
>I only can seem to find a way of listing the contents of the first tar
>file, not the number of tar files on the tape. I have that sinking
>feeling I have been using a rewind option without being aware of it.
>


To look at further archives you were almost doing the correct thing, just
needed to use the no-rewind device with the mt command, before running the
tar command (assuming that there are further archives on the tape!).

Also, fsf 1 skips one archive, taking you to the start of the second one if
you were positioned at the start of tape. Similarly fsf2 takes you to the
start of the 3rd.

Hope this helps,


Dave.