Export JVM memory information on CentOS, and export jvm memory from centos

Export JVM memory information on CentOS, and export jvm memory from centos
First, check the Tomcat process Id:

[root@iZ25Z ~]# ps aux | grep javawww       2111  4.0 23.5 1637648 452756 ?      Sl   10:12   4:35 /usr/java/jdk1.7.0_80/bin/java -Djava.util.logging.config.file=/usr/local/tomcat/conf/logging.properties ...　　

We can see that the Tomcat process Id is 2111, and then use the JDK built-in tool jmap to export the memory information in the entire JVM:

# Jmap-dump: format = B, file = file name [pid] jmap-dump: format = B, file = mm. hprof 2111

However, we get this prompt:

jmap -dump:format=b,file=mm.hprof 21112111: Unable to open socket file: target process not responding or HotSpot VM not loadedThe -F option can be used when the target process is not responding

This is because I run this statement as the root user, but my tomcat process runs as a www user (you can see it using ps aux | grep java ). We can find a file like/tmp/hsperfdata _ $ USER/$ PID on the machine. When we execute jmap to display the above information, first, check whether the USER executing the command is consistent with the USER of the file 'file _ $ user'. If the USER is inconsistent, switch to the same one and then execute the command. Or, as prompted, simply add the-F parameter:

jmap -F-dump:format=b,file=mm.hprof 2111

Man page describes this option as follows:

-F Force. Use with jmap -dump or jmap -histo option if the pid does not respond. The live suboption is not supported in this mode.

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