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HBase, mail # user - Please review my GC options, and give me some advice.


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Please review my GC options, and give me some advice.
Azuryy Yu 2012-12-09, 09:55
hi,
I found sometimes yong gc is very slow, it paused more than 14 seconds.
GC log:
1383.531: [GC 1383.531: [ParNew: 235968K->26176K(235968K), 14.1752210 secs]
1518208K->1356662K(4168128K), 14.6084490 secs] [Times: user=9.77 sys=0.14,
real=14.61 secs]
Total time for which application threads were stopped: 14.6241190 seconds

jstat : (jstat -gc -h 10 20010 1000)

          S0C    S1C    S0U    S1U      EC       EU        OC
OU       PC     PU    YGC     YGCT    FGC    FGCT     GCT
          26176.0 26176.0 26176.0 26176.0 209792.0 209792.0 3932160.0
1315008.8  163840.0 22007.9    434  330.795  14      3.943  334.738
         26176.0 26176.0 26176.0 26176.0 209792.0 209792.0 3932160.0
1315008.8  163840.0 22007.9    434  330.795  14      3.943  334.738
         26176.0 26176.0 26176.0  0.0   209792.0   0.0    3932160.0
1330486.2  163840.0 22007.9    434  344.970  14      3.943  348.913

Eden, S0, S1 are all full, then yong gc paused more than 14 seconds. please
give me some advice, appreciate much!

1) I used:
java version "1.7.0_09"
Java(TM) SE Runtime Environment (build 1.7.0_09-b05)
Java HotSpot(TM) 64-Bit Server VM (build 23.5-b02, mixed mode)

2) My JVM options as follow(yong objects have a short life generally, so
-Xmn256m):
-Xmx4g -Xms4g -Xmn256m  -server -verbose:gc -XX:+PrintGCTimeStamps
-XX:+PrintGCDetails -XX:+PrintGCApplicationStoppedTime
-XX:-HeapDumpOnOutOfMemoryError -XX:+UseGCLogFileRotation
-XX:NumberOfGCLogFiles=9 -XX:GCLogFileSize=20m -XX:+DisableExplicitGC
-XX:+UseCompressedOops -XX:PermSize=160m -XX:MaxPermSize=160m
-XX:GCTimeRatio=19 -XX:SoftRefLRUPolicyMSPerMB=0 -XX:SurvivorRatio=8
-XX:MaxTenuringThreshold=6 -XX:+UseParNewGC -XX:+UseConcMarkSweepGC
-XX:+CMSParallelRemarkEnabled -XX:CMSInitiatingOccupancyFraction=70
-XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=0
-XX:+CMSClassUnloadingEnabled -XX:CMSMaxAbortablePrecleanTime=300
-XX:+CMSScavengeBeforeRemark
-XX:ErrorFile=/usr/local/hase/logs/rs_error_gc.log
-Xloggc:/usr/local/hbase/logs/rs_gc.log
-XX:HeapDumpPath=/usr/local/hbase/logs/rs_error.hprof