Will rsync support btrfs file system?

[Benjamin R. Haskell]

On Sun, 6 Dec 2009, Charles Marcus wrote:

> On 12/6/2009, Louise Hoffman (louise.hoffman at gmail.com) wrote:
> > The way I read that, it's not something rsync-specific. It sounds
> > like btrfs would allow the generation of a list of files, which rsync
> > (or tar, or zip, or whatever) could accept. (Rsync obviously being
> > the best choice, :-) )
> 
> So, I wonder if inotify could be leveraged to do the same thing - this 
> would be file-system agnostic...
> 

inotify seems too transient to me... It would require some process 
actively listening for changes, and you'd have the possibility of losing 
the information during power failure, for example.

That is, with a journaling FS-based solution (I assume 'btrfs' uses 
journaling), you don't lose that list, because the FS journals the change 
before it commits it to the FS.  Whereas with inotify, you're only getting 
the info after the change is made, so there's the possibility of loss 
during the window between 'change is made' and 'inotify reports change to 
listener'.

Maybe that's a small enough chance that it's acceptable, though.  (i.e. if 
the tracking-changes-between-backups process detects a power failure, it'd 
fall back to something else, like recursively checking mtime's.)

Do things like 'locate' use inotify at this point?  If so, that'd probably 
be a good jumping-off point for something like this.

Or, maybe the inotify-based solution would just be for dailies, and full 
weekly backups would compensate for the above-mentioned problem.

Best,
Ben