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From Christopher Schultz <>
Subject Re: Tomcat Memory Status?
Date Sun, 23 Jul 2006 14:36:43 GMT

> So with: Free memory: 2.17 MB Total memory: 5.84 MB Max memory: 63.56
> MB
> I really have approximately 63.56MB - 5.84MB + 2.17MB = 59.89MB
> available which isn't really near tapping the server out. Start
> worrying when Total Memory creeps up near Max Memory.


There /are/ cases where the JVM needs to allocate a lot of memory in a
short period of time, and the GC cannot keep up with the allocation
requirements, and you get either an OutOfMemoryError or sometimes other
weird things going on. In these cases, it makes sense to first set the
initial heap size to the same as the max heap size, so that you get all
your Java heap memory allocated at once, before any real work gets done.
(This is why many folks on this list recommend setting init=max).

The other possibility is that you app simply needs more memory. If you
cache a lot of data, or store a lot of stuff in users' sessions, or
simply expect a ton of traffic with a lot going on at once, you may need
to raise your heap size.


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