gclog排查的必備基本參數

##gclog基本參數

-verbose:gc
-verbose:sizes
-Xloggc:/tmp/gclogs/gc.log
-XX:+UseGCLogFileRotation
-XX:NumberOfGCLogFiles=5
-XX:GCLogFileSize=2M
-XX:+PrintGCDetails
-XX:+PrintGCDateStamps
-XX:+PrintGCTimeStamps 
-XX:+PrintTenuringDistribution
-XX:+HeapDumpOnOutOfMemoryError 
-XX:HeapDumpPath=/

##heap設置

-server 
-Xmx4g 
-Xms4g

##perm的設置 ###java8以前

-XX:PermSize=128m 
-XX:MaxPermSize=256m

###java8

-XX:MetaspaceSize=128m
-XX:MaxMetaspaceSize=256m

##G1的gc參數

-XX:+UseG1GC 
-XX:MaxGCPauseMillis=10 
-XX:GCPauseIntervalMillis=200

##cms的gc參數

-XX:+DisableExplicitGC  
-XX:+UseParNewGC 
-XX:+UseConcMarkSweepGC
-XX:+ExplicitGCInvokesConcurrent
-XX:+CMSScavengeBeforeRemark
-XX:+CMSParallelRemarkEnabled

##ps的gc參數

-XX:+DisableExplicitGC 
-XX:+UseParallelGC 
-XX:+UseParallelOldGC 
-XX:+UseAdaptiveSizePolicy

##doc

• Garbage Collection Visualization
• Java永久代去哪兒了