[OpenAFS] Re: Possible explanation(s) for obvious performance problems?

Andrew Deason adeason@sinenomine.net
Sat, 24 Apr 2010 16:01:24 -0500

On Sat, 24 Apr 2010 20:00:05 +0200
Holger Rauch <holger.rauch@empic.de> wrote:

> Any ideas as to where that bad performance might come from? (I do have
> encryption enabled, but since it's only plain DES encryption on
> current machines that most likely can't be an explanation for the
> performance problem).

Well, there's one way to find out for sure...

Simon covered server tweaking in general, but for throughput on a server
that's not particularly loaded, my first guess might be -rxpck
specifically. I recall some people have reported significant throughput
improvement when it's raised to even 2000 or higher.

To see if it's the client or the server that's the bottleneck, you could
try a throughput test with afsio or afscp. If that yields a much faster
result, you're likely hitting bottlenecks in the cache manager code. It
could also be slower, though, if you've tweaked afsd's rx settings, as I
don't think afsio or afscp allow you to tune those. (afsio is in
src/venus, afscp is src/tests)

Andrew Deason