[OpenAFS] Strange caching failures

Derrick Brashear shadow@gmail.com
Thu, 28 Feb 2013 09:44:57 -0500


start with FileLog on the fileserver and see what errors for B (or D or...) a=
t around the time it breaks.

Derrick


On Feb 28, 2013, at 9:39, Stephan Wonczak <a0033@rrz.uni-koeln.de> wrote:

>  Hi all!
>  for the past few weeks, we are struck with a very weird behavior regardin=
g cache updates of AFS clients. It looks like sometimes the callback does no=
t work and one client is stuck with an older version of the file in question=
. Example:
>=20
>  Write to file 'foo' on client A every five minutes.
>  Clients B,C and D dutifully update their caches and see the updates
>  After some time, suddenly Client B dows not see the updates any more, whi=
le clients C and D continue working fine.
>  A 'fs flush foo' on client B corrects the problem.
>  Other files are *NOT* affected and are updated fine on Client B.
>=20
>  This behavior is not really repeatable, though, sometimes it is client D t=
hat stops working, or any other client.
>  When taking into account that the clients I am talking about here are web=
 servers, you can imagine that this behavior is less than desirable.
>=20
>  Now for the versions:
>  Clients are a mix of 1.4.x and 1.6.x (mainly 1.6.1-1.el5 and 1.4.12-el5, w=
ith other versions thrown into the mix).
>  Servers are version 1.4.11-el5.
>  OS on both clients and server is RHEL5
>=20
>  It might be a coincidence, but we became aware of this problem shortly af=
ter updating a bunch of clients to 1.6.1-1.el5.
>=20
>  Any ideas on how to go about debugging this?
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>    Dipl. Chem. Dr. Stephan Wonczak
>=20
>        Regionales Rechenzentrum der Universitaet zu Koeln (RRZK)
>        Universitaet zu Koeln, Weyertal 121, 50931 Koeln
>        Tel: +49/(0)221/470-89583, Fax: +49/(0)221/470-89625
> _______________________________________________
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>=20