Tomcat:Definindo a quantidade de memória utilizada pelo Tomcat

Configurando o Apache Tomcat
Edite o arquivo catalina.sh e adicione a entrada

JAVA_OPTS="$JAVA_OPTS -server -Xms256m -Xmx512m"

Salve e Feche o arquivo.

Reinicie então Tomcat

> ./shutdown.sh > ./startup.sh

Verificando

> ps -efw | grep java root    12039     1  0 10:21 pts/2    00:00:10 /usr/java/latest/bin/java -server -Xms256m -Xmx512m -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.util.logging.config.file=/opt/apache-tomcat-6.0.18 /conf/logging.properties -Djava.endorsed.dirs=/opt/apache-tomcat-6.0.18/endorsed -classpath :/opt/apache-tomcat-6.0.18 /bin/bootstrap.jar -Dcatalina.base=/opt/apache-tomcat-6.0.18 -Dcatalina.home=/opt/apache-tomcat-6.0.18 -Djava.io.tmpdir=/opt/apache- tomcat-6.0.18/temp org.apache.catalina.startup.Bootstrap start root    13008 10539  0 10:52 pts/2    00:00:00 grep java