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My experience with tapes ended shortly after DAT tape appeared (used 1/4" then 8mm), so this may be out of date; however, I associate tape backups of disk partitions with dump(8), restore(8), and rmt(8), along with cpio(1) for data files.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@notredame.ac.jp