[Deploying Sakai] Sakai 2.9 performance issue
dlhaines at umich.edu
Tue May 28 05:15:35 PDT 2013
At Michigan we've found that examining a heap dump usually makes the
memory problem clear. YourKit does this well.
If you reset all the caches from the memory tool does performance get
better? That's not a long term solution but can help diagnose (and just
might provide a short term bandaid).
On Mon, May 27, 2013 at 9:24 AM, Aaron Zeckoski <azeckoski at unicon.net>wrote:
> I suggest you try changing one of your nodes JVM settings and drop the
> following from it.
> -Xms5000m -Xmx5000m -XX:+UseConcMarkSweepGC
> -XX:+ExplicitGCInvokesConcurrent -XX:+CMSIncrementalMode -verbose:gc
> -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDetails
> -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps
> Putting those in severely limits the JVM autotuning (also known as
> (plus the slowdown from all the GC monitoring)
> Also, "-Dsun.lang.ClassLoader.allowArraySyntax=true" is no longer needed.
> Then monitor the node using jstat or something similar and compare it
> to the performance of the other nodes. You can tweak things from there
> but in most cases you will find the tuner handles things better on its
> On Mon, May 27, 2013 at 8:58 AM, David Horwitz <david.horwitz at uct.ac.za>
> > Hi All,
> > We are/did experience a performance issue last week we would like to seek
> > community input on.
> > Some back ground:
> > Kernel 1,3,x based (1.3.2 msub with KNL-1068 applied)
> > Java 1.6.0_30
> > mysql 5.1.68
> > Javaopts:
> > -server -d64 -Xms5000m -Xmx5000m -XX:MaxPermSize=640m
> > -Dhttp.proxyHost=campusnet.uct.ac.za -Dhttp.proxyPort=8080
> > -XX:+UseConcMarkSweepGC -XX:+ExplicitGCInvokesConcurrent
> > -XX:+CMSIncrementalMode -verbose:gc -XX:+PrintGCApplicationStoppedTime
> > -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps
> > -Duser.language=en -Duser.region=ZA -Djava.awt.headless=true
> > -Dnetworkaddress.cache.ttl=60
> > -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false
> > -Dsun.lang.ClassLoader.allowArraySyntax=true -Dhttp.agent=Sakai
> > -Djava.net.preferIPv6Addresses=false -Djava.net.preferIPv4Stack=true
> > Symptoms:
> > Randomly nodes enter a state where they become increasingly unresponsive
> > to longer and more frequent full GC operations. Until Friday we seemed to
> > see this randomly with a higher incidence after the end of the lectures,
> > during extensive online testing on Friday we experienced this across all
> > nodes. It seems to be unrelated to the node running times as we have
> seen it
> > on nodes that have been restarted in the last 24 hours as well as others
> > that have been running for some time.
> > Any one seen similar issues? As a preventative we have upgraded to the
> > latest 1.6 jdk (1.6.0_45) but are far from convinced this is the problem.
> > Thanks
> > David
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