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Re: fsfs revprop packing in f5 Re: Does fsfs revprop packing no longer allow usage of traditional backup software?

From: Daniel Shahaf <danielsh_at_elego.de>
Date: Wed, 6 Jul 2011 22:42:58 +0300

Stefan Sperling wrote on Wed, Jul 06, 2011 at 21:40:00 +0200:
> On Wed, Jul 06, 2011 at 02:30:15PM -0500, Hyrum K Wright wrote:
> > After a bit of thinking and discussion, Daniel and I have come up with
> > what we think is an acceptable solution, and I'm posting it here for
> > validation. (Daniel, please correct me if I've gotten something
> > wrong.)
> >
> > Revision properties will *not* be packed in an sqlite database, but
> > will instead be packed in a single packfile, much like revision are to
> > today. The key difference is that instead of having a separate
> > manifest file, the manifest will be prepended to the packfile, meaning
> > the two can be atomically replaced in the case of a propedit.
> > This solution has at least of couple of advantages:
> > * No need to check a separate "edited" file before reading the packfile
> > * The repo maintains consistency in the case of a filesystem copy
> > (helpful for backups)
> >
> > Revprops wouldn't be packed until explicitly asked to do so by
> > 'svnadmin pack' which means the frequent post-commit revprop editing
> > wouldn't pose a performance problem. In addition, the revprop
> > packfile manifest information won't be cached, since the manifest may
> > change. We don't anticipate this to be a problem, since it only adds
> > an extra seek() to the revprop lookup process (rather than the open()
> > + seek() in the rev packing world).
> >
> > Comments?
>
> Sounds good to me, if this is the last non-trivial change we squeeze
> in before release... IIRC this code was initially written within
> a couple of days anyway during one of the hackathons in Munich.
>

Are you thinking of rep-sharing? Revprop packing is a pquerna patch.

> I hope we have good regression tests for revprop packing (I haven't
> checked)?
Received on 2011-07-06 21:44:17 CEST

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