Re: [rdiff-backup-users] Safe to mirror backup dir with rsync?

[Steven Willoughby]

On 12/23/2009 05:55 PM, Engel Sanchez wrote:
> Hi Alex. My understanding could be wrong, but this is the scenario that I'm 
> trying to avoid:
>
> 1) Machine 1 has the original data and backs it up locally to /backup
> 2) Machine 2 rsyncs /backup to local /backup every day
> 3) Machine 2 is rsyncing /backup, and right then machine 1 dies for good (fire, 
> flood, apocalypse)
>
> At that point in time, machine 1 is dead and /backup in machine 2 is not a 
> valid rdiff-backup directory, so you can't restore your data from it anymore.  
> If Machine 2 was instead using rdiff-backup on the original sources, /backup 
> would have an incomplete backup, but previous data would not be lost, so you 
> can restore from it even if it was interrupted.

Use rsync's --delay-updates.  That will narrow the window of failure 
significantly.

If that's not enough, create a temporary hard-linked copy of /backup on 
machine 2:

set -e

cp -al /backup /backup.new
rsync -a --del machine1:/backup/ /backup.new/
mv /backup /backup.old
mv /backup.new /backup
rm -r /backup.old

Steven