[svlug] Back up strategies? - was Data recovery services?

[Scott Hess]

On 2/26/06, Skip Evans <skip at bigskypenguin.com> wrote:
> What are some backup strategies people use and
> what are some you'd recommend? Big tape drive?
> We'll be rsync'ing the a new server back to this
> one for a while. Is that a popular method?

I've used many strategies over the years, including backup to multiple
classes of tape, backup to read-write optical devices and removable
magnetic devices (before CDs), data-only backup to CD-R, some system
backup to CD-R systems (Mondo comes to mind, provides a bootable
restore process which is cool), backup to DVD-R, and, lastly,
rsnapshot backup to a large hard drive.  The latter is the first
system which I've actually _liked_ as opposed to considering it a
necessary evil.  It's also the first which I've actually managed to
have working to backup _all_ my systems.

http://www.rsnapshot.org/

rsnapshot is a system built on rsync (there are a couple other such
systems out there, rsnapshot is just the one I used).  At every
backup, it copies the existing backup instance to a new place, then
uses rsync to pull any changes over.  Unchanged files are hardlinked
between the backup instances, so you can simultaneously have backups
for the past 7 days, the past 4 weeks, etc, without too much expense
in overhead (at least if the bulk of your data doesn't change much
between backups).  To keep things robust, I have a system dedicated to
the rsnapshot server - I seldom login to the system, and don't export
anything read/write, and don't run any unnecessary daemons, so it's
pretty unlikely that I'll accidentally mess things up.  Once a month I
mirror the backup archive to one of a pair of external drives, which I
otherwise leave disconnected and turned off, and which I rotate
between home and office.

My thinking on having all these copies is:

 - If I lose an individual system, I can restore from the backup server.
 - If I lose the backup server, I can rebuild it from the most recent offline
   mirror, or from the other systems.
 - If I lose everything that's powered on, I can restore from the
offline mirror.
 - If I lose my home office, I still have a somewhat-stale copy at work.
 - If I lose Northern California, well ... I don't know, yet :-). 
I've considered having
   a dedicated system well offsite, but I'm not certain it's worth the expense.

Nice things about this system:

 - I exported the snapshot archive read-only, so I can easily verify
if things are
   working using standard filesystem operations.
 - Trivial to check an old config file without doing the tape-/cd-loading dance.
 - Commodity hardware, if anything dies I can replace it in a couple hours.
 - Disks are getting cheaper faster than I can fill them :-).
 - Other than the mirror-and-rotate step, everything is automated, don't even
   need to swap media.
 - I now find upgrading a _breeze_.  I used to do an elaborate dance involving
   never being destructive, because I didn't trust my backups.  Now I
do trust my
   backups, and they are very easy to verify.  I can upgrade, and compare what
   the old system had to what the new system has and iterate until it has
   everything I really need, rsync over the user data, and I'm good to go.

Basically, I've been a super-happy rsnapshot user for a year and a
half, and I can't think of a reason to stop being happy...

-scott