jdk1.7 与jdk 1.8 生产环境JVM参数

jdk 1.7 生产虚拟机参数（添加到 catalina.sh中）

#JAVA_OPTS=”-Xmx8000M -Xms8000M -Xmn1024M -XX:PermSize=2048M -XX:MaxPermSize=2048M -Xss256K -XX:+DisableExplicitGC -XX:SurvivorRatio=1 -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+CMSParallelRemarkEnabled -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=0 -XX:+CMSClassUnloadingEnabled -XX:LargePageSizeInBytes=128M -XX:+UseFastAccessorMethods -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSInitiatingOccupancyFraction=80 -XX:SoftRefLRUPolicyMSPerMB=0 -XX:+PrintClassHistogram -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -Xloggc:/tmp/gc.log” 

jdk 1.8 （注意新版本metaspace 代替了旧版本PermGen space）

JAVA_OPTS=”-server -Xmx8g -Xms8g -Xmn2g  -XX:MetaspaceSize=2g -XX:MaxMetaspaceSize=2g -Xss256k -XX:+DisableExplicitGC  -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:LargePageSizeInBytes=128m -XX:+UseFastAccessorMethods -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSInitiatingOccupancyFraction=70 -Duser.timezone=GMT+8 -XX:+PrintClassHistogram -XX:+PrintGCDetails -XX:+PrintGCTimeStamps  -XX:+PrintGCDateStamps   -XX:+PrintHeapAtGC  -XX:+HeapDumpOnOutOfMemoryError  -XX:HeapDumpPath=/tmp/b2b_interface.dump   -Xloggc:/tmp/b2b_interface_gc.log -verbose:gc -Xmixed -XX:-CITime”

JAVA_OPTS=”-server -Xmx100m -Xms100m -Xmn25m  -XX:MetaspaceSize=40m -XX:MaxMetaspaceSize=40m -Xss256k -XX:+DisableExplicitGC  -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:LargePageSizeInBytes=128m -XX:+UseFastAccessorMethods -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSInitiatingOccupancyFraction=70 -Duser.timezone=GMT+8 -XX:+PrintClassHistogram -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC  -XX:+HeapDumpOnOutOfMemoryError  -XX:HeapDumpPath=/tmp/b2b_interface.dump   -Xloggc:/tmp/b2b_interface_gc.log -verbose:gc -Xmixed -XX:-CITime”

jmap -heap pid

Attaching to process ID 31448, please wait…
Debugger attached successfully.
Server compiler detected.
JVM version is 25.162-b12

using parallel threads in the new generation.
using thread-local object allocation.
Concurrent Mark-Sweep GC

Heap Configuration:
   MinHeapFreeRatio         = 40
   MaxHeapFreeRatio         = 70
   MaxHeapSize              = 104857600 (100.0MB)
   NewSize                  = 26214400 (25.0MB)
   MaxNewSize               = 26214400 (25.0MB)
   OldSize                  = 78643200 (75.0MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 41943040 (40.0MB)
   CompressedClassSpaceSize = 33554432 (32.0MB)
   MaxMetaspaceSize         = 41943040 (40.0MB)
   G1HeapRegionSize         = 0 (0.0MB)

Heap Usage:
New Generation (Eden + 1 Survivor Space):
   capacity = 23592960 (22.5MB)
   used     = 19414032 (18.514663696289062MB)
   free     = 4178928 (3.9853363037109375MB)
   82.28739420572917% used
Eden Space:
   capacity = 20971520 (20.0MB)
   used     = 18428176 (17.574478149414062MB)
   free     = 2543344 (2.4255218505859375MB)
   87.87239074707031% used
From Space:
   capacity = 2621440 (2.5MB)
   used     = 985856 (0.940185546875MB)
   free     = 1635584 (1.559814453125MB)
   37.607421875% used
To Space:
   capacity = 2621440 (2.5MB)
   used     = 0 (0.0MB)
   free     = 2621440 (2.5MB)
   0.0% used
concurrent mark-sweep generation:
   capacity = 78643200 (75.0MB)
   used     = 64297224 (61.31861114501953MB)
   free     = 14345976 (13.681388854980469MB)
   81.75814819335938% used