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Re: Backup



On Tue, Jun 20, 2000 at 09:57:48AM -0600, Dean Allen Provins wrote:
> > 
> > 
> > 
> > Hi,
> > 
> >   I'm thinking to get a scsi backup tape for the Potato
> >   box.  I'd like to know what is the recommended drive
> >   and what software should be used.
> > 
> >   I also have this dump question.  Would the backup software
> >   append the backup files to the end of the tape or overwrite
> >   it everytime?
> > 
> >   TIA!
> > 
> > ---
> > tcp
> 
> I use an HP DAT drive (35xxx - now called Surestore, I think).  Its
> been use for about 5 years (every night) without a problem.  I've used
> 'tar' and 'dump' and both work just fine.

I'll second the Surestore recommendation.  I've got a 2GB DAT which has
been used a little less frequently <g>, but does a great job.  Note that
if you plan on aquiring more than about 15 tapes, the cost point
between DAT and Travan/QIC breaks down about even.  DAT is solid,
dependable, proven technology, and the media are cheap and reusable.
Just what you're looking for in a backup.  The downside is that
capacity, relative to today's drive sizes, is somewhat limited.  I can
get ~4GB compressed, which works for me, but you'll have to look at
higher capacity tape drives for your 9-40GB disks out now.

> Whether or not the software appends or not, is in part predicated on
> where the tape is when the run gets going.  Device /dev/nst0 doesn't
> rewind, while /dev/st0 does.  If the backup software always rewinds,
> and doesn't search for an EOF marker before writing again (i.e. knows
> to append) you'll be out of luck.
> 
> If you use commercial software, check the specs first.  If you write a
> simple 'tar' script, you can do what you want.

On this.  Unless you have specific requirements to meet (eg:  management
can't keep from fucking with a technical decision), I'd choose the
simplest backup methods possible.  My own local backup script is:

    #!/bin/bash

    # Create backups of /etc, /home, /usr/local, and...

    mt rewind
    tar cvf /dev/nst0 /etc
    tar cvf /dev/nst0 /home
    tar cvf /dev/nst0 /usr/local

    # and selected /var directories
    tar cvf /dev/nst0 /var/backups
    tar cvf /dev/nst0 /var/cache/apt
    tar cvf /dev/nst0 /var/lib
    tar cvf /dev/nst0 /var/log
    tar cvf /dev/nst0 /var/www
    mt rewoffl

Tar isn't the sexiest thing out there (honey is <g>), but damned if it
doesn't work, and if the tools for accessing archives aren't available
on every flavor of Unix, and most lesser operating systems, not to
mention boot, rescue, and minimal installations of Linux.  You *will* be
able to get at your data.

Other general recommendations -- dump, cpio, and apio.  I'd generally
*avoid* using an integrated backup management solution -- far less
portable, and you may *not* be able to get at your data, unless you are
part of a large and well-supported organization.  You get some plusses
-- usually a searchable index or other log of what was archived, but it
costs you in terms of flexibility.

-- 
Karsten M. Self <kmself@ix.netcom.com>         http://www.netcom.com/~kmself
  Evangelist, Opensales, Inc.                       http://www.opensales.org
   What part of "Gestalt" don't you understand?      Debian GNU/Linux rocks!
     http://gestalt-system.sourceforge.net/      K5: http://www.kuro5hin.org
GPG fingerprint: F932 8B25 5FDD 2528 D595  DC61 3847 889F 55F2 B9B0

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