./setenv.sh - example setenv.sh with defaults set for minimal time spent in garbage collection

setenv.sh

#! /bin/sh

# discourage address map swapping by setting Xms and Xmx to the same value
# http://confluence.atlassian.com/display/DOC/Garbage+Collector+Performance+Issues
export CATALINA_OPTS="$CATALINA_OPTS -Xms512m"
export CATALINA_OPTS="$CATALINA_OPTS -Xmx512m"

# Increase maximum perm size for web base applications to 4x the default amount
# http://wiki.apache.org/tomcat/FAQ/Memoryhttp://wiki.apache.org/tomcat/FAQ/Memory
export CATALINA_OPTS="$CATALINA_OPTS -XX:MaxPermSize=256m"

# Reset the default stack size for threads to a lower value (by 1/10th original)
# By default this can be anywhere between 512k -> 1024k depending on x32 or x64
# bit Java version.
# http://www.springsource.com/files/uploads/tomcat/tomcatx-large-scale-deployments.pdf
# http://www.oracle.com/technetwork/java/hotspotfaq-138619.html
export CATALINA_OPTS="$CATALINA_OPTS -Xss192k"

# Oracle Java as default, uses the serial garbage collector on the
# Full Tenured heap. The Young space is collected in parallel, but the
# Tenured is not. This means that at a time of load if a full collection
# event occurs, since the event is a 'stop-the-world' serial event then
# all application threads other than the garbage collector thread are
# taken off the CPU. This can have severe consequences if requests continue
# to accrue during these 'outage' periods. (specifically webservices, webapps)
# [Also enables adaptive sizing automatically]
export CATALINA_OPTS="$CATALINA_OPTS -XX:+UseParallelGC"

# This is interpreted as a hint to the garbage collector that pause times
# of <nnn> milliseconds or less are desired. The garbage collector will
# adjust the  Java heap size and other garbage collection related parameters
# in an attempt to keep garbage collection pauses shorter than <nnn> milliseconds.
# http://java.sun.com/docs/hotspot/gc5.0/ergo5.html
export CATALINA_OPTS="$CATALINA_OPTS -XX:MaxGCPauseMillis=1500"

# A hint to the virtual machine that it.s desirable that not more than:
# 1 / (1 + GCTimeRation) of the application execution time be spent in
# the garbage collector.
# http://themindstorms.wordpress.com/2009/01/21/advanced-jvm-tuning-for-low-pause/
export CATALINA_OPTS="$CATALINA_OPTS -XX:GCTimeRatio=9"

# The hotspot server JVM has specific code-path optimizations
# which yield an approximate 10% gain over the client version.
export CATALINA_OPTS="$CATALINA_OPTS -server"

# Disable remote (distributed) garbage collection by Java clients
# and remove ability for applications to call explicit GC collection
export CATALINA_OPTS="$CATALINA_OPTS -XX:+DisableExplicitGC"

echo "Using CATALINA_OPTS:"
for arg in $CATALINA_OPTS
do
    echo ">> " $arg
done
echo ""

echo "Using JAVA_OPTS:"
for arg in $JAVA_OPTS
do
    echo ">> " $arg
done
echo "_______________________________________________"
echo ""

I am so grateful for this, it completely changed my production server's performance, and opened up a lot of useful knowledge. Thank you

Thank you so much!

This is just what I was looking for—thanks, @terrancesnyder ! One comment/question: you say you want to "discourage address map swapping by setting Xms and Xmx to the same value" but then use different vales in your script (-Xms64m & -Xmx512m), a couple of lines later; was this an error, or did you change your mind about the ideal values and forget to update the comment?

Thanks for sharing.

With Java 7, I see a "Stack Size Too Small" and then tomcat refuses to startup. Recommended size is 228k.

Thanks. Very useful.
I 've found the same message from tomcat "The stack size specified is too small, Specify at least 228k", so i need to increase the Xss by using this value " -Xss256k" and to prevent a permgen space i use a different value : "-XX:MaxPermSize=512m"

Thanks a lot

This is very cool. It increases my tomcat performance significantly. Thanks.

Thanks a lot!

Thanks for sharing!

Thanks

Thanks.

Thanks .. Really very helpful..

Thanks for the knowledge sharing dude, much appreciated

Hi Guys i have installed Alfresco community 5.0.e on Ubuntu 14.04 LTS and i cant find setenv.sh file. What can I do i want to run javascript debugger

Thanks!

The various CATALINA_OPTS such as -Xms , Xmx, XX:MaxPermSize seem to be independant of physical RAM.
Is it right ?
What are the default values (for Tomcat 7) ?

It does not work for me
Creating setenv.sh with just export CATALINA_OPTS="$CATALINA_OPTS -Xmx512m" in it crashes tomcat7 on start.
$CATALINA_OPTS is not defined in my standard tomcat7 installation on Debian Jessie.
Should I define it somewhere ?
Regards

thank you so much

Thanks for sharing.