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Re: Backing up a Linux system

How  would I  go about reinstalling  the packages  in the
event of  disaster? What  if my packages  are a combination  of slink,
potato, etc.?  -chris

On Thu, 3 Aug 2000 kmself@ix.netcom.com wrote:

> On Wed, Aug 02, 2000 at 05:28:14PM +0100, bsamuels@datamansys.co.uk wrote:
> > Debian Potato (Frozen) with Slink  KDE.
> > 
> > I want to be able to backup my linux system to scsi tape (nst0)
> > such that, if my hard drive falls into little pieces one bright
> > sunny day, I can boot from a rescue floppy and restore the lot
> > onto a new drive without having to re-install anything.
> > 
> > I plan to use afio for the backup in conjunction with the
> > Tomsrtbt rescue floppy (an amazing piece of work).
> afio is a good choice.  I use tar.  It's prevelant, though slightly less
> robust.
> > Most parts of the system are straightforward and I could include
> > mount point directories, such as /cdrom, as long as there is
> > nothing actually mounted then they would, at least, be
> > automatically re-created.  
> However, if you do have something mounted beneath a mount point it
> generally *will* be backed up.  You'll end up with a rather redundant
> copy of that CDROM you left in the drive last night.
> > I wouldn't need to backup /tmp.
> > What about /dev?  Could the device files be backed up without
> > backing up the contents of the said devices?  I did see once that
> > Midnight Commander could copy a complete linux system onto
> > another partition so I assume that backing up the /dev directory
> > could be done.
> GNU tar handles /dev files properly, though strictly you don't need to
> back this up.  See below.
> > I'm assuming that the contents of /proc, including any
> > sub-directories, are generated each time at startup and all that
> > would need to be done would be to re-create the actual directory.
> In general, you don't *need* to back up anything that's a standard part
> of the system.  This would include:
> System directories: /bin /sbin /dev /lib /usr /initrd
>     Each of these contains *only* files added by the distribution, and
> 	for which your backups can't necessarily be trusted to restore to
> 	proper state.  An OS reinstall is appropriate (and buys you an
> 	upgrade, if desired).  The information will be correctly created.
> 	Generally, you don't need to back up these trees.
> Temporary fils: /tmp 
>     This is flushed by the system on each reboot anyway (watch your
>     boot messages).  Backups unnecessary.
> Secondary mount points: /mnt /net
>     YMMV, but you generally won't want to back up arbitrary remote
> 	filesystems, and frequently don't need to back up removable devices
> 	(floppy, cdrom, zip, jaz, mo) mounted under /mnt or another mount
> 	point.  Backups probably irrellevant.
> Virtual FS and recovery:  /proc /lost+found 
>     /proc is a virtual filesystem.  It doesn't actually "exist" in a
> 	sense of storage, it's an interface to kernel-space data and state.
> 	It isn't "created" at boot, it's probably more accurate to say that
> 	information under /proc is made available on demand.  /lost+found is
> 	where lost clusters are placed by e2fsck.  Generally you're not
> 	interested in these (though YMMV).  Backup unnecessary and possibly
> 	impossible.
> Stray links:  /opt
>     If you've implemented /opt as a link to /usr/local, you don't need
> 	to back it up seperately.  If you've created a seperate filesystem,
> 	ask yourself why, move everything in it to /usr/local, create an
> 	appropriate link, and remove /opt from your backup schedule.  Backup
> 	a sign of poor FS layout (IMVAO).
> Persistant system state: /var
>     There are parts of /var you'll want to keep, much of it you can
> 	discard.  See the example below for more guidance.  Note that you
> 	*will* want to save anything relating to your packaging system
> 	(there are apt and dpkg trees under /var), duplicates of system
> 	files under /var/backups, system logs, and possibly web space.
> 	There are arguments on both sides of archiving spools (print, mail,
> 	news, squid, fax, etc.).  I choose not to.  Backups on a selected
> 	basis.
> Stuff you *REALLY* want to save:  /etc /root /usr/local /home
>     This is the non-distribution, non-remote, non-volatile, valuable
> 	part of your system.  Hard-won configurations, local apps and
> 	data, and user space.  Backups mandetory.  Early and often.
> 	Validate your backups.
> My own system backup script follows.  This is for an aging single-user
> Linux box, and is run typically every few days.  Fits well on a single
> 2.0 GB SCSI DAT-90 DDS tape, with 1 2.4 GB and 2x 2.1 GB disks.
> -------------------- <begin system-backup> --------------------
> #!/bin/bash
> # Create backups of /etc, /home, /usr/local, and...
> mt rewind
> tar cvf /dev/nst0 /etc
> tar cvf /dev/nst0 /root
> 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
> -------------------- <end system-backup> --------------------
> -- 
> 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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