automatic hard linking

[William Stearns]

Good afternoon, all,
 	(Sorry for the late reply!  :-)

On Wed, 23 Jul 2008, t.littlefield at comcast.net wrote:

> Hello,
>
> A co-worker and I were talking about various ways to do 'backups' to try and
> prevent data loss.  The topic came around to a file system we had used
> at a previous job.  I can't remember the specifics, but we believe it was
> a Network Appliance system.
>
> One of the cool features it offered was a series of hourly, nightly and
> a monthly backup of files.  We kind of surmised that it was some sort of
> hard linking of the same file name in a different directory...  i.e.
>
> ~/foo.txt
>
> hourly.0/~/foo.txt
>
> So, if you accidentally deleted your home directory copy, you could still recover
> it for a short time.  Once it made it past X hours, the file would start getting
> removed from the hourly.n directories.  We were never admins on the box
> nor do we have experience with it, so the hard link is just a theory...

 	This is exactly the approach I used in rsync-backup:

http://www.stearns.org/rsync-backup/

 	The script is currently set up to do nightly snapshots, but could 
be tuned without too much trouble to do hourly snapshots if that was 
needed.
 	Cheers,
 	- Bill

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