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From Apache Wiki <>
Subject [Tomcat Wiki] Update of "FAQ/Monitoring" by ChristopherSchultz
Date Wed, 04 Jul 2012 21:13:11 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Tomcat Wiki" for change notification.

The "FAQ/Monitoring" page has been changed by ChristopherSchultz:

New page:
Monitoring of a running Tomcat instance can be done in several ways, but observing a Tomcat
instance via JMX beans will give you the best information available through standard interfaces
(i.e. JMX). You can find information about [|connecting
to Tomcat via JMX] in the Tomcat Users' Guide. Rather than repeating that information here
(which is mostly about configuration, connection, etc.), please go read the official documentation.

This page is intended to be a community-curated collection of useful JMX beans that may be
useful to you ''after'' you have made your JMX connection and want to observe interesting
data through Tomcat's (and other) JMX beans.

== JVM Memory Information ==

You will certainly want to inspect your JVM's memory usage. Here are some JMX beans and attributes
that can be used to do so.

JMX Bean: java.lang:type=Memory
Attribute: HeapMemoryUsage

The attribute value is a which contains 4 keys: committed,
init, max, and used. The 'used' key is probably the most useful (or a combination of 'used'
/ 'max' to get a memory-usage metric as a ratio).

JMX Bean: java.lang:type=MemoryPool,name=CMS Perm Gen
Attribute: Usage

Similar to the HeapMemoryUsage MXBean described above, this one will give you information
about the "PermGen" heap generation. Depending upon your garbage collection and other memory
settings, you might have different MXBeans under java.lang:type=MemoryPool with different
names. You should inspect each one to determine if they would be useful for you to inspect.

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