[Gluster-devel] AFR filesystem inconsistency?

Krishna Srinivas krishna at zresearch.com
Sun Feb 17 17:02:28 UTC 2008

Hi Martin,

Since selfheal is done only on demand this issue is seen.
However you can get around this problem if after bringing
up the downed server you do a "find . > /dev/null" from the
root directory (which would call lookup() on every directory,
lookup() code has the code to fix the issue you are seeing)


On Feb 17, 2008 11:21 AM, Martin Fick <mogulguy at yahoo.com> wrote:
> I am particularly interested in the AFR translator and
> am curious about how it is supposed to work and what
> are the plans for its future.  I am running the debian
> packages 1.3.7-0, mentioned on the wiki and have found
> the following behavior:
> I setup AFR to replicate to two volumes, A & B, each
> on separate machines.  Both these volumes are
> "exported" as a server.  I mount the AFR result from a
> client to say /mnt and I copy five files to /mnt,
> (1,2,3,4,5).  I then shutdown one of the servers (A)
> and delete file 1 and then restart that server.  After
> it is restarted if I look at the contents of subvolume
> A and it still contains files 1,2,3,4,5, whereas
> subvolume B correctly only contains 2,3,4,5.  Is this
> normal behavior?  If I perform an ls on the client
> /mnt I correctly get just 2,3,4,5 and then if I check
> the subvolumes again, they are in sync 2,3,4,5.  So
> far, so good, the client always sees the "correct"
> view of the filesystem.
> But, trouble starts if I perform a similar scenario
> slightly differently.  Assuming I know have files
> 2,3,4,5 on both subvolumes and the client /mnt.  I
> shutdown A again and then delete file 2 from /mnt.  I
> bring A back up and wait a while but do not access
> /mnt.  I then shutdown B!  Now if I do an ls on /mnt
> it still shows me file 2 since it was never deleted
> from A and A does not seem aware that B had it delete
> on it.  This is "incorrect" behavior since someone
> deleted file 2 from /mnt and without doing anything to
> /mnt, it reappears!  Is this by design, a bug, or
> simply a not addressed yet issue?
> Are there plans to enhance the AFR translator so that
> this kind of inconsistency is avoided?  Or if this is
> desired behavior for some, are there any plans to
> build another translator that can be placed above the
> AFR that would ensure consistency even when nodes go
> down?
> Thanks,
> -Martin
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