[OpenAFS] Re: VLDB corruption

Michael Meffie mmeffie@sinenomine.net
Tue, 11 Nov 2014 14:39:55 -0500

On Sun, 9 Nov 2014 00:17:42 +0200
Kostas Liakakis <kostas@physics.auth.gr> wrote:

> On 11/08/2014 06:05 PM, Andrew Deason wrote:
> > That particular warning doesn't seem like it would cause problems; just
> > taht we're using up extra unused space in the db. Would you be willing
> > to share your (partially-corrupt) vldb blob? That way we could try to
> > make vldb_check handle that issue.
> Oh, good. I though so but it is a relief to read it from somebody who 
> knows better. My database is not big, about 1.5MB is all, but if this 
> may help other cells which far bigger databases I am all in for helping 
> you guys resolve it.
> I just mailed my vldb to Mike to test his patch. I can forward you a 
> copy if you like as well.

Thank you for sharing your vldb file. I was able to confirm the records
were actually empty, and the free chain was broken. Gerrit 11598 fixes
the free chain. If accepted, I'll push a fix for a future point release.

> > It does seem like maybe a better way to fix corruption errors would be
> > to dump the vldb to a text format, and be able to restore that back to a
> > db blob. But, that's not what we have now.
> Right, this is what I had in mind. I had done the same in the past, 
> prompted by people in this list, with pt_util for my protection database 
> to remove some entries prdb_check -fix woundn't touch. So when I saw the 
> dump option in there it rung a bell.
> Thank you all for your time.

The vldb is different from the prdb, in that it needs to match what is reality
on the file servers, which is the purpose of the vos syncserv/syncvldb tools.
But I've often thought it be nice to have some tooling that could export the
vldb to some useful text format (yaml, xml, sql, etc) and be able to import the
text to build a vldb.

Michael Meffie <mmeffie@sinenomine.net>