This conversation seems to have dropped off the users list. Forwarding
to get it archived.

Regards
Julian

---------- Forwarded message ---------
From: Julian Sedding <[email protected]>
Date: Thu, Dec 6, 2018 at 10:38 AM
Subject: Re: Corrupt Oak segment store - how to recover last good revision?
To: Michael Dürig <[email protected]>
Cc: Julian Sedding <[email protected]>


Hi Michael

Thanks for your reply!

I was working on disaster recovery, particularly a segment tar store
(1.6.14) that got corrupted due to out-of-disk. Most likely during
online compaction. Therefore it was acceptable to lose any content
created after the corruption had occurred.

Rather than append the revision to the journal, I truncated any later
revision from the journal. The net effect should be the same I expect.
In any case, it work fine and the repository is back in operation
since Monday night. After offline compaction of the segment store, its
size was reduced to ~25GB (still a lot IMHO but lots better than
250GB).

As things go, I used the same strategy again this week to recover a
tree of accidentally deleted nodes from another repository. So thanks
a lot for confirming the validity of this approach. Even though it
should not be used lightly and not without a good understanding of the
consequences.

Regards
Julian
On Wed, Dec 5, 2018 at 8:31 PM Michael Dürig <[email protected]> wrote:
>
>
> Hi Julian
>
> Just append the found good revision to the end of the journal log
> following the format of the preceding lines. Afterwards you could run
> offline compaction to get rid of garbage. Please note though that this
> will roll back your repository to the identified good revision. All data
> from all later revisions will be lost.
>
> Michael
>
>
> On 03.12.18 14:16, Julian Sedding wrote:
> > Hi all
> >
> > I'm analysing a segment store that was most likely corrupted after an
> > out-of-disk event. The system is running  Oak 1.6.14.
> >
> > Currently I am running oak-run check on the segment store, which is
> > unfortunately ~250GB in size after several system maintenance
> > operations being run last night (e.g. purgin of old versions, possibly
> > tar compaction, maybe others).
> >
> > In case the check finds a "good" revision. I didn't find how to reset
> > it to that revision. Do I just remove all later journal entries?
> >
> > Thanks & regards,
> > Julian
> >

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