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Re: backup compress on the fly

Ron Johnson wrote:
On Fri, 30 Sep 2005 13:56:45 -0500
Mike McCarty <mike.mccarty@sbcglobal.net> wrote:

Joe Mc Cool wrote:


If you are making archives, or you are backing up a system which,
if it failed and you lost everything it would be a terrible
disaster, then I recommend you *not* to compress your backups.

Compressed file formats are notoriously intolerant of medium
errors. It might be better to do subset backups each of which
fits onto a single tape.

What kind of tape drive doesn't put CRC data in each block?

The point is that, if there is an error, all the CRCs in the
world won't put the data back together again. If one uses
cpio or tar to put something onto a tape, and there is an
error, there is hope of resynchronizing a little later, and
getting some or even most of the data off of the tape. OTOH, if the
whole image on tape is a compressed one, then tar or gunzip or whatever
is simply going to complain that the one (and only) file in
the compressed archive is corrupt and unrecoverable.

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