HAMMER history friendly backup tool

[Tomohiro Kusumi]

An editor like vim (under a certain condition vim uses) can't retain
the history as well.

If the application creates a new inode with the same path, the history
is gone, because hammer looks up btree for history using inode # along
with other keys.
It's the same path, but different entity.



2016-04-25 6:27 GMT+09:00 Bomrek Koganvutram <232.20711 at chiffre.aleturo.com>:
> * 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