On 29/11/07 16:43, "Jon Bagshaw" <[log in to unmask]> wrote:
> What are your JVM settings, especially the HEAP settings?
> Are you running with the 64bit JVM?
>
> The 64bit JVM allows you to allocate more memory at the trade off that
> java garbage collection takes longer.
Note that this can mitigated with the concurrent low pause collector if you
have the spare CPUs (and cycles thereon). See
http://java.sun.com/docs/hotspot/gc5.0/gc_tuning_5.html for the lowdown.
Disclaimer: We've been running this on development for a long time, but I
haven't moved it to production.
To the OP, I suggest turning on garbage collection statistics at the very
least, which will allow you to see if you have a potential issue there.
Assuming you are on the Sun JDK, do that by adding the following to
bbconfig.jvm.options.extra.tomcat before running PushConfigUpdates:
-verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps
The statistics will go into catalina.out.
JVM tuning after that point, in our case, became a simple matter of
adjusting heap, perm and stack sizes, waiting for Blackboard to fall over
(took about a week, if I remember correctly), tweaking it again and
reiterating until we found the sweet spot. This is impossible to do without
the statistics.
Ceri
--
Senior Solaris Platform Engineer
Information Services, Cardiff University
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