[Building Sakai] Java, Tomcat Tuning

[Katherine Faella]

Hi all,

We are about to begin the new semester.  We have upgraded to Sakai 
2.9.x, running with Java 6 and Tomcat 7.

We have experienced about 20% growth in usage each year since our first 
semester in the Fall of 2009.  Last year we ran over 3000 concurrent 
users each week day afternoon/evening with peaks reaching towards 3200.

Last year on Sakai 2.8.x, I ran 11 instances of Sakai on three physical 
servers with Apace mod_proxy_ajp.  These were my java opts:

export JAVA_OPTS="-server -d64 -XX:+UseParNewGC -Xms6000m -Xmx6000m 
-XX:PermSize=512m -XX:MaxPermSize=512m -verbose:gc 
-XX:+PrintGCTimeStamps -XX:+PrintGCDetails -Djava.awt.headless=true 
-Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false
-Dsun.lang.ClassLoader.allowArraySyntax=true -XX:+UseConcMarkSweepGC 
-XX:CMSInitiatingOccupancyFraction=80 -XX:+DisableExplicitGC"

I am pondering whether to go with fewer, larger instances this year.  
Our hardware is the three servers with dual-quad core processors and 32G 
of memory on each server.

I am looking for any suggestions, warnings, helpful tidbits to help me 
decide.

Thanks in advance,
Kathy Faella

-- 
Katherine Faella                        tel: (401) 874-4469
Sr. Technical Programmer                kmf at uri.edu
University of Rhode Island
University Computing Systems(UCS)
210 Flagg Road
Kingston, Rhode Island  02881