At Mon, 6 Feb 2012 16:04:18 -0500, Alan McKay wrote:
>
> > I don't think so - I'm fairly sure I've seen GNUtar complain about bad
> > headers, say 'skipping to next header' and then find something. It
> > won't do that if you used the -z option because you generally can't
> > recover from errors in compression
> >
> >
> Bam! As an aside to my current line of questioning, I was looking for an
> excuse not to compress and you just gave it to me! Yay!
>
> Compressing makes it nigh impossible to know whether or not the data will
> fit on the tape without doing a test compress ahead of time, which can take
> several hours depending on the amount of data.
My experience with tapes ended shortly after DAT tape appeared
(used 1/4" then 8mm), so this may be out of date; however, I
associate tape backups of disk partitions with dump(8), restore(8),
and rmt(8), along with cpio(1) for data files. Some shared software
used to come on 1/4" tape in tar format. The only compression I
recall (vaguely) was standard ("POSIX" on GNU/Linux) compress(1P).
Anyway, I would never put non-standard compression on tape that
might be used on a different POSIX system.
- Greg
Greg Peterson <peterson at notredame.ac.jp>