Re: [vserver] Very serious hashify mysql/innodb conflict causes major data loss

From: John A. Sullivan III <jsullivan_at_opensourcedevel.com>
Date: Sat 13 Jun 2009 - 22:14:49 BST
Message-Id: <1244927689.6377.7.camel@jaspav.missionsit.net.missionsit.net>

On Sat, 2009-06-13 at 21:58 +0100, Ed W wrote:
> John A. Sullivan III wrote:
> >
> > Thanks! That saved me some serious grief - John
> >
>
>
> It would still be very interesting to try and find what's causing the
> issue though. The logic of vhashify should only create hard links
> between identical files. In fact I'm curious how/why it's even updating
> directory times?
>
> I don't have the logic of the hash open right now, but presumably we
> need to unlink one side and hard link the otherside (or perhaps it
> copies/moves one side into the cache folder and hard links everything
> else?) The point being I guess if you had an open file which got
> hardlinked then you might be unlucky enough to end up writing to
> something which was now unlinked?
>
> That your writes to the innodb log files have stopped suggests that
> perhaps part of the log files got linked while open? However, this
> seems unlikely given that the data files ought to be completely
> different in all your vservers?
>
> Do you do anything special which might cause these files to look
> identical before running vhashify?
>
> Ed W
Interesting. I'm unable to give a lot of thought to it right now.
Certainly the innodb log files were in use when hashify ran. I can not
think of a reason why it would think there would be an identical file
unless hashify will hash files with the same content on the same
vserver. In that case, aren't there two innodb log files? I don't know
enough about either hashify or innodb. Thanks - John

-- 
John A. Sullivan III
Open Source Development Corporation
+1 207-985-7880
jsullivan@opensourcedevel.com
http://www.spiritualoutreach.com
Making Christianity intelligible to secular society
Received on Sat Jun 13 22:13:16 2009
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