*BSD News Article 27901


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From: vax@sylvester.cc.utexas.edu (Vax)
Newsgroups: comp.os.386bsd.questions
Subject: Re: backup: tar vs cpio?
Date: 28 Feb 1994 03:37:41 -0600
Organization: The University of Texas - Austin
Lines: 50
Message-ID: <2kse15$4np@sylvester.cc.utexas.edu>
References: <MARK.822.2D6F935C@ardsley.business.uwo.ca>
NNTP-Posting-Host: sylvester.cc.utexas.edu

In article <MARK.822.2D6F935C@ardsley.business.uwo.ca>,
Mark_Bramwell <MARK@ardsley.business.uwo.ca> wrote:
>Currently I am doing this from root....
>tar cvf /dev/rst0 *
>Is there a reason that I should be doing something else?
>I want a backup that I can use for individual files as well as a full system 
>restore.

Call me old-fashioned, but I have found through trial and error, that
dump and restore are less error-prone when restoring individual files, and
directory subtrees.  Try, for example, extracting all -but- a specific
directory hierarchy when using GNUtar.  Ick.

Here's why not to use tar (subjective opinion, bugs may be fixed):
When using -d to compare a tar file to the pwd,
tar -df /dev/rmt8 (no period)
When using -c to create a file containing pwd and all subdirs,
tar -cf /dev/rmt8 . (period)
When extracting with -x to the pwd, do;
tar -xf /dev/nrst0 (no period)

It is unpleasant to find inconsistencies (IMHO) like this, after
spending hours and hours waiting for the tape to run through
(I have 525MB quarter-inch tapes, they take hours)

restore has a nifty interactive interface, much like a Unix shell,
that gives you this nice warm feeling that everything will work right
the first time, and it usually does.

Besides, it also has support for multi-level backups (that's incremental)
and does cool things like that.  The down side is that you probably can't
read it from MS-DOS, but who cares. :)

You should also put it on your rescue diskette.. speaking of which,
I have a diskette that I use.  It has:

vi fsck fdisk restore halt reboot disklabel newfs mount init chmod rm cp
mt df mkdir sync sh cat (as well as /etc stuff, /dev stuff, mdec stuff, etc)

Each is the "full" version of the program, so you can "rm -rf" and offending
tree, etc.  I use "echo *" instead of "ls".

I find this disk so useful, I'm tempted to make it ftp-able.  Would anyone
else like such a disk?  They are decievingly hard to make.  There are many
dependencies for some programs.  I have tested this disk, and it has everything
a tape-user (who uses dump(1)) would need to recover the system from a file
system problem.
-- 
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