[OpenAFS] Understanding questions backup volume

[Sergio Gelato]

* Lars Schimmer [2006-02-10 15:03:51 +0100]:
> So my job is to search for third party backup tools and use vos dump.
> I need to think about a nice efficient system. In real only the home
> folders are really of interest for long time backup, maybe a streamer is
> to much of hardware for this. A DVD-R could do this job, to.

"vos dump" supports incrementals, so that's fairly efficient as long as
your users aren't in the habit of making frequent, small changes to very
big files (in which case one may wish for some kind of rsync- or xdelta-like
support built into the backup tool; if network bandwidth isn't a
bottleneck this can be done by post-processing the dump files,
no modifications required to AFS itself).

I currently store my AFS backups as a series of successive dumps (a full
one from time to time, followed by nightly incrementals), but for
near-line storage one could imagine a more RCS-like strategy: always
store the latest version of every vnode in full (maybe compressed), 
and prior versions as compressed deltas if that saves space. 
Purge old versions when space gets tight, perhaps after making 
an archival copy to off-line media. Has this already been implemented?
If not, I might do it myself, time permitting.