[ale] Backup software

[Michael B. Trausch]

On Wed, 2010-06-30 at 18:18 +0000, Brandon Wood wrote:
> I am looking to create an image of a live system and want to know what
> software is suggested for this purpose. I've done some searching and
> came across 'mondo' and am trying it out now. 

What I typically do is use a multiple partition setup---and conventions
for storing data---to make things easier to backup.

On any given system, I backup the following regularly:

 - /etc
 - /srv
 - /home

I also backup a snapshot of the package list that is installed; since
the package manager's configuration (for apt/dpkg, anyway) all lives
in /etc, I can recreate the system just from those things.  Then,
restoration involves nothing more than installing a clean operating
system, and restoring the package list, then going to single-user mode
and restoring from the backups.

That said, if you want to take an image of all of a system at a given
point in time, I would use something like LVM and then just create a
compressed image of the filesystem---use dd and pipe it to gzip, bzip2,
or xz.  I prefer xz because of the size of the compressed output, but it
also takes the longest to do, so if you need things to happen quickly,
use gzip.

Lately, however, I've been getting away from whole-system images and
just focusing on being able to quickly rebuild a system; that seems far
more efficient to me.  If you store backups in a very highly compressed
format, restoring in this way can be significantly faster than
decompressing an entire stream.  Plus, it's filesystem independent and
doesn't tie you to a particular partition layout or a particular size
(other than the minimum required size plus reasonably expected growth)
for a filesystem.

	HTH,
	Mike