HAMMER history friendly backup tool

[Bomrek Koganvutram]

* Predrag Punosevac on Tue, Mar 15, 2016 at 07:02:06PM -0400:
> It looks increasingly unlikely that I will get any suggestions to the
> original question so I am just going to post my own "solution" to the
> original problem.

> I remember that after Unison sync the file history was lost. What I
> didn't remember until today was that Peeter noticed that the same was
> true with rsync 

> https://marc.info/?l=dragonfly-users&m=135885584004499&w=2
> 
> which indeed shares the main algorithm with Unison.  He also noticed
> that using scp or even a cp over NFS (my observation which is fully
> tested) will play well with HAMMER history. So long story short it would
> be fairly easily to cook up such a backup tool which will traverse the
> on my home directory (running OpenBSD) and just cp the files which have
> changed since the last run. I also tested rdiff-backup if anybody cares
> and the result is the same as with rsync and unison.

Your post is now somewhat dated, but just in case:  Have you tried using
‘--inplace’ with rsync?  My guess is that it’s the way how rsync and
similar tools create their files that breaks HAMMER history:  Instead of
overwriting the file, it is replaced by a new file.  Since it’s a -new-
file, a new history will start there.

With ‘--inplace’, rsync instead overwrites the original file (which has
all kinds of drawbacks, that’s why it isn’t the default), but for your
use case perhaps it’s worth a try.

> I remember that after Unison sync the file history was lost. What I
> didn't remember until today was that Peeter noticed that the same was
> true with rsync 

I have used Unison a few years back, and it -does- use the same
replace-with-new-file-approach, pretty much for the same reasons.

> Personally I decided to run HAMMER snapshot as a cron job after rsync
> and in that way preserve the older version of files. 

That would have been my second suggestion; it may not be as convenient
as ‘undo’, but at least the data is known to be preserved.


Sorry for the late answer; I flagged it a few weeks ago, but then work
got the better of me and I completely forgot. :o)


Cheers,
    Bomrek


-- 
Was wir brauchen sind ein paar verrückte Leute
-- seht euch an, wohin uns die Normalen gebracht haben.
		-- George Bernard Shaw