[TAG] Backup software/strategies
Kapil Hari Paranjape
kapil at imsc.res.in
Thu Jul 12 07:47:28 MSD 2007
On Wed, 11 Jul 2007, Ben Okopnik wrote:
> All of us know - at least I hope we do - that we should all be doing
> regular backups; that's a given.
Like one of the "existence" proofs in mathematics --- this gives no
hint of how one arrives at a solution :-)
> Can anyone here think of a sensible backup plan for the situation that
> I've described - laptop, external backup, arbitrary schedule - and some
> way to set up a schedule that work with that?
There are (at least) two different reasons why one (who uses a
laptop or desktop) might create a backup:
1. Protection against catastrophic break down or lack of
access to the laptop's disk.
2. Protection against accidental deletion of important work
As far as (1) is concerned, I have already written out a kind of
strategy in LG #140. To that one can add the fact the laptops are not
"always on" so that "cron" type scheduling is irrelevant. So one
approach is to periodically schedule "laptop maintenance mornings":
a. Do a backup.
b. Run all those pending cron jobs with "anacron -s".
c. Send all those pending "popularity-contest" and bug report
mailings, run "cruft" and do house-keeping.
d. Possibly clean the real cruft from the screen and
For (a), I would use a simple script that invokes LVM snapshots and
rsync. I would not bother with incremental backups for (1).
One solution for (2) is to use version control for *everything*
important. With a typical system like "git" this means all that
is backed-up uses about double (or more[*]) space than it would
otherwise. However, it also means that recovery of deleted files is
quick and easy.
Since (1) takes care of backing up the repository as well, you have
the necessary incremental backup too.
Having said this, I have only partially implemented (2) and (1) is
often postponed. Note that (1) tends to run into lunch and the late
evening as well :-)
Obviously, the strategy for a network of computers that share files
and are always on would be quite different.
[*] When is an old version to be dumped? Look at Rene's posting for
some thoughts on this.
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