Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!basser!ultima!hades!greyham
From: greyham@hades.OZ (Greyham Stoney)
Newsgroups: comp.unix.i386
Subject: backups on 386/ix - some pronblems using GNUtar; any hints?
Keywords: backups, 386ix, GNUtar, tape streamer
Message-ID: <481@hades.OZ>
Date: 4 Dec 89 16:13:50 GMT
Organization: Ausonics Pty Ltd, Sydney, Australia
Lines: 47

I'm having a couple of problems trying to do automatic (as much as possible)
backups on our 386/ix machine, which I need a few hints on.

The machine has a 300MB hard disk, partitioned into 3 filesystems as
follows:

> /         :	Disk space:  31.98 MB of  51.26 MB available (62.39%).
> /usr      :	Disk space:  26.95 MB of 115.09 MB available (23.42%).
> /usr2     :	Disk space:   5.03 MB of 114.84 MB available ( 4.38%).
> 
> Total Disk Space:  63.97 MB of 281.21 MB available (22.75%).

(Ok, I lied; there's also a DOS partition in there for VPIX, but that's
irrelevant). The idea of this is that was can do full backups of the
system by using one tape for each filesystem. Our tape drive is 120Mbyte;
so we should be able to do a full dump and end up with a / tape, a
/usr tape, and a /usr2 tape.

I don't want to do that every day though, so I want to do an overnight
incremental dump of everthing that changed since the last full dump.

Anyway, so it looked to me like GNUtar could do this, since it's tar
compatible, and can do date-based incrementals. [any other suggestions
are welcome]. There are a few troubles though:
(this is using GNU tar version 1.07; I believe this is the latest?)

1) When the tape is completely full, GNUtar reports "error opening
directory ...." for every directory not yet covered. At least, this seems
to be what's happening. If the tape drive is 120Mb, and the filesystem is
115Mb, how come the tape fills up at all anyway when doing a full dump???.

2) When doing a compressed TAR, gnutar's return code incorrectly indicates
that the tar went OK even if the tape is write protected. Our dump script
relies on this return code to know whether or not to update the automatic
tape-contents register we've got.

Has anyone got any hints, or even just general ideas on the best strategy
I should adopt here?. I don't want to hack GNUtar (much);

		any suggestions at all are welcome.

					Greyham.

-- 
/*  Greyham Stoney:                            Australia: (02) 428 6476  *
 *     greyham@hades.oz  - Ausonics Pty Ltd, Lane Cove, Sydney, Oz.      *
 *                ISDN: Interface Subscribers Don't Need                 */