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From: cgd@eden.CS.Berkeley.EDU (Chris G. Demetriou)
Newsgroups: comp.unix.bsd
Subject: Re: [386BSD] backup program with compressed output?
Date: 4 Dec 92 22:26:50
Organization: Kernel Hackers 'r' Us
Lines: 27
Message-ID: <CGD.92Dec4222650@eden.CS.Berkeley.EDU>
References: <1992Dec5.050125.18752@mnemosyne.cs.du.edu>
NNTP-Posting-Host: eden.cs.berkeley.edu
In-reply-to: smace@nyx.cs.du.edu's message of Sat, 5 Dec 92 05:01:25 GMT
there are several reasons you wouldn't want to compress data
you're backing up, unless the compression is integral
to the backup scheme.
This glaring one sticks out:
If it's not well-integrated into the backup stream,
compression leaves you with the following vulnerability:
One bit error can render your dump (after that bit)
completely unusable.
That, of course, assumes an adaptive compression algorithm, but
i don't think a non-adaptive compression algorithm would work
very well, in any case...
if you really need to compress it, i think "dd" has multi-volume
output capability... (if not, there are versions of dd which do,
and for which you could probably find the source...)
good luck, and my your backups be fast and frequent... 8-)
Chris
--
Chris G. Demetriou cgd@cs.berkeley.edu
"Sometimes it is better to have twenty million instructions by
Friday than twenty million instructions per second." -- Wes Clark