Seems like the problem there after I upgrade to "OpenJDK Runtime Environment (IcedTea6 1.9.2)". So it is not related to the bug I reported two days ago.
Can somebody else share some info with us? What's the java environment you used? Is it stable for long-lived cassandra instances? best regards, hanzhu On Thu, Dec 16, 2010 at 9:28 PM, Zhu Han <schumi....@gmail.com> wrote: > I've tried it. But it does not work for me this afternoon. > > Thank you! > > best regards, > hanzhu > > > > On Thu, Dec 16, 2010 at 8:59 PM, Matthew Conway <m...@backupify.com>wrote: > >> Thanks for debugging this, I'm running into the same problem. >> BTW, if you can ssh into your nodes, you can use jconsole over ssh: >> http://simplygenius.com/2010/08/jconsole-via-socks-ssh-tunnel.html >> >> Matt >> >> >> On Dec 16, 2010, at Thu Dec 16, 2:39 AM, Zhu Han wrote: >> >> > Sorry for spam again. :-) >> > >> > I think I find the root cause. Here is a bug report[1] on memory leak of >> > ParNewGC. It is solved by OpenJDK 1.6.0_20(IcedTea6 1.9.2)[2]. >> > >> > So the suggestion is: for who runs cassandra of Ubuntu 10.04, please >> > upgrade OpenJDK to the latest version. >> > >> > [1] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6824570 >> > [2] http://blog.fuseyism.com/index.php/2010/09/10/icedtea6-19-released/ >> > >> > best regards, >> > hanzhu >> > >> > >> > On Thu, Dec 16, 2010 at 3:10 PM, Zhu Han <schumi....@gmail.com> wrote: >> > >> >> The test node is behind a firewall. So I took some time to find a way >> to >> >> get JMX diagnostic information from it. >> >> >> >> What's interesting is, both the HeapMemoryUsage and NonHeapMemoryUsage >> >> reported by JVM is quite reasonable. So, it's a myth why the JVM >> process >> >> maps such a big anonymous memory region... >> >> >> >> $ java -Xmx128m -jar /tmp/cmdline-jmxclient-0.10.3.jar - localhost:8080 >> >> java.lang:type=Memory HeapMemoryUsage >> >> 12/16/2010 15:07:45 +0800 org.archive.jmx.Client HeapMemoryUsage: >> >> committed: 1065025536 >> >> init: 1073741824 >> >> max: 1065025536 >> >> used: 18295328 >> >> >> >> $java -Xmx128m -jar /tmp/cmdline-jmxclient-0.10.3.jar - localhost:8080 >> >> java.lang:type=Memory NonHeapMemoryUsage >> >> 12/16/2010 15:01:51 +0800 org.archive.jmx.Client NonHeapMemoryUsage: >> >> committed: 34308096 >> >> init: 24313856 >> >> max: 226492416 >> >> used: 21475376 >> >> >> >> If anybody is interested in it, I can provide more diagnostic >> information >> >> before I restart the instance. >> >> >> >> best regards, >> >> hanzhu >> >> >> >> >> >> >> >> On Thu, Dec 16, 2010 at 1:00 PM, Zhu Han <schumi....@gmail.com> wrote: >> >> >> >>> After investigating it deeper, I suspect it's native memory leak of >> JVM. >> >>> The large anonymous map on lower address space should be the native >> heap of >> >>> JVM, but not java object heap. Has anybody met it before? >> >>> >> >>> I'll try to upgrade the JVM tonight. >> >>> >> >>> best regards, >> >>> hanzhu >> >>> >> >>> >> >>> >> >>> On Thu, Dec 16, 2010 at 10:50 AM, Zhu Han <schumi....@gmail.com> >> wrote: >> >>> >> >>>> Hi, >> >>>> >> >>>> I have a test node with apache-cassandra-0.6.8 on ubuntu 10.4. The >> >>>> hardware environment is an OpenVZ container. JVM settings is >> >>>> # java -Xmx128m -version >> >>>> java version "1.6.0_18" >> >>>> OpenJDK Runtime Environment (IcedTea6 1.8.2) (6b18-1.8.2-4ubuntu2) >> >>>> OpenJDK 64-Bit Server VM (build 16.0-b13, mixed mode) >> >>>> >> >>>> This is the memory settings: >> >>>> >> >>>> "/usr/bin/java -ea -Xms1G -Xmx1G ..." >> >>>> >> >>>> And the ondisk footprint of sstables is very small: >> >>>> >> >>>> "#du -sh data/ >> >>>> "9.8M data/" >> >>>> >> >>>> The node was infrequently accessed in the last three weeks. After >> that, >> >>>> I observe the abnormal memory utilization by top: >> >>>> >> >>>> PID USER PR NI *VIRT* *RES* SHR S %CPU %MEM TIME+ >> >>>> COMMAND >> >>>> >> >>>> 7836 root 15 0 *3300m* *2.4g* 13m S 0 26.0 2:58.51 >> >>>> java >> >>>> >> >>>> The jvm heap utilization is quite normal: >> >>>> >> >>>> #sudo jstat -gc -J"-Xmx128m" 7836 >> >>>> S0C S1C S0U S1U *EC* *EU* *OC* >> >>>> *OU* *PC PU* YGC YGCT FGC FGCT >> >>>> GCT >> >>>> 8512.0 8512.0 372.8 0.0 *68160.0* *5225.7* *963392.0 >> 508200.7 >> >>>> 30604.0 18373.4* 480 3.979 2 0.005 3.984 >> >>>> >> >>>> And then I try "pmap" to see the native memory mapping. *There is two >> >>>> large anonymous mmap regions.* >> >>>> >> >>>> 00000000080dc000 1573568K rw--- [ anon ] >> >>>> 00002b2afc900000 1079180K rw--- [ anon ] >> >>>> >> >>>> The second one should be JVM heap. What is the first one? Mmap of >> >>>> sstable should never be anonymous mmap, but file based mmap. *Is it >> a >> >>>> native memory leak? *Does cassandra allocate any DirectByteBuffer? >> >>>> >> >>>> best regards, >> >>>> hanzhu >> >>>> >> >>> >> >>> >> >> >> >> >
