backing up shadow files with rsync?

[Patrick O'Callaghan]

On Thu, 2011-02-17 at 11:09 +1030, Tim wrote:
> On Wed, 2011-02-16 at 13:45 -0430, Patrick O'Callaghan wrote:
> > Rsnapshot is just a useful front-end to rsync. It keeps snapshots of
> > an entire tree ordered by backup generation (using hard links to avoid
> > duplicating files).
> 
> If you link, instead of duplicating, then you only have one backup of a
> file.  So, if that backup has a problem...?
> 
> Did I miss something obvious?

You pays your money and you takes your choice. If you want every backup
of your 10GB home directory to take up another 10GB of space, go for it.
Most people don't actually want that. They assume (naively or not) that
the backup medium is itself sufficiently reliable, for example I'm doing
it on a NAS configured with mirrored disks, which is fine for my
purposes. YMMV of course.

Here's a listing of the current space occupancy:

$ sudo rsnapshot du
28G     /storage/Backups/rsnapshot/daily.0/
7.5G    /storage/Backups/rsnapshot/daily.1/
2.8G    /storage/Backups/rsnapshot/daily.2/
430M    /storage/Backups/rsnapshot/daily.3/
1.1G    /storage/Backups/rsnapshot/daily.4/
431M    /storage/Backups/rsnapshot/daily.5/
437M    /storage/Backups/rsnapshot/daily.6/
523M    /storage/Backups/rsnapshot/weekly.0/
16G     /storage/Backups/rsnapshot/weekly.1/
11G     /storage/Backups/rsnapshot/weekly.2/
571M    /storage/Backups/rsnapshot/weekly.3/
4.0G    /storage/Backups/rsnapshot/monthly.0/
37G     /storage/Backups/rsnapshot/monthly.1/
3.5G    /storage/Backups/rsnapshot/monthly.2/
112G    total

(Each number is a delta from the previous one). So I'm using 112G
instead of 400G or so. Plus the nightly backup is done in around 30
minutes. Works for me, and I actually had a disk failure on the NAS but
since it's mirrored I could keep going while getting a replacement.

In the end it's all a matter of cost (in the broadest sense) vs benefit,
which you have to work out for yourself.

poc