Re: ftape format warning!!!
Ken Gaugler writes:
Ken> I had a nasty surprise using ftape to dump my filesystems for
Ken> archival right before repartitioning my hard drive. I wanted to let
Ken> people know about this in case they were not already aware.
Ken>
Ken> If you plan to dump several filesystems to one tape (that is, more
Ken> than one session on a tape) you need to erase the tape using mt
Ken> FIRST!!! Otherwise you will not be able to read any sessions beyond
Ken> the first.
You could have read the Ftape-HOWTO before attempting to do this. It says:
6.4. Putting more than one tar file on a tape
To put more than one tar file on a tape you must have the mt utility.
You will probably have it already, if you got one of the mainline
distributions, e.g. Slackware or Debian.
tar generates a single Tape ARchive (that's why it is called `tar')
and knows nothing about multiple files or positioning of a tape, it
just reads or writes from/to a device. mt knows everyting about moving
the tape back and forth, but nothing about reading the data off the
tape. As you might have guessed, tar and mt in conjunction, does the
trick.
By using the nrft[0-3] (nftape) device, you can use `mt' to position
the tape the correct place (`mt -f /dev/nftape fsf 2' means step over
two ``file marks'', i.e. tar files) and then use tar to read or write
the relevant data.
Ken> There were only two sessions on my tape. Sadly, the second session
Ken> contained the /usr filesystem, so I lost everything :(
Moreover, you can simplify your life by using a program as tob which reads
from several filesystems. Debian tob's package is in the admin section.
--
Dirk Eddelb"uttel http://qed.econ.queensu.ca/~edd
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