unix环境中，java运行环境配置优化

#!/bin/sh

ulimit -n 1000000

export JAVA_OPTS="-Dcom.sun.management.jmxremote.port=18950 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false"

logfile=log/log_`date -d today +"%Y%m%d%H%M%S"`.log

ls *.jar > $logfile

echo `date` >> $logfile

echo -------start-------- >> $logfile

nohup java $JAVA_OPTS -Xmx15G -Xms15G -Xmn2g -XX:NewSize=6G -XX:MaxNewSize=6G -XX:MaxPermSize=512m  -XX:ReservedCodeCacheSize=64m  -XX:+CMSClassUnloadingEnabled -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:CMSInitiatingOccupancyFraction=50  -XX:+CMSPermGenSweepingEnabled -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=3  -XX:+PrintClassHistogram -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -Xloggc:gc.log -server -jar *.jar >> $logfile 2>&1 &