[OpenAFS] Re: Tuning the -daemons.

Jan Johansson janj@it.su.se
Mon, 7 Feb 2011 20:55:11 +0100

Thank you for your interest in helping out here.

So I will start with the easy questions and try to get into the
kernel later.

Based on the History I believe that the problem is the
client/cache manager.

We had this kind of problems before.

In the first round the client made the server crash. An upgrade
of the client from Ubuntu Karmic to Ubuntu Lucid solved that.

Next the server got overloaded so we upgraded from Ubuntu Hardy
to Ubuntu Lucid. Threw out some more of the old FreeBSD and
stopped running virtual servers in ESX.

Some time passed and we got blocking fileservers tuning of the
fileservers solved some of the problems. We also threw some
"random" options at the client and redesigned the webmail to make
users stick to a single IMAP backend.

This time around we are rebuilding the IMAP servers for mail
clients and since we have a little time before the users arrive
with the pitch forks I am trying to understand what the "right"
settings should be.

In the earlier cases the server would stop serving any clients so
unrelated services (like webservers) would stop and the users
would complain about not beeing able to save their files. This
time it is only the single client/cachemanager that is affected.

The server is running Ubuntu Lucid Lynx with the included OpenAFS
1.4.12+dfsg-3 package. Fileserver is started with
"-L -abortthreshold 1024 -syslog"

The client is running Ubuntu Lucid Lynx with the included OpenAFS 
1.4.12+dfsg-3 package. The "random" options on the webmail
backends are "-stat 15000 -dcache 6000 -daemons 6
-volumes 256 -rxpck 2000 -files 50000 -afsdb -dynroot -fakestat"
the once I am testing now are "-daemons 6 -afsdb -dynroot

To the best of my knowledge there never was a problem running
rxdebug <client> 7001. I know for a fact the rxdebug <server>
700X works without problem during the hangs.

Jan J