Hi,

We are a call centre and the application is a scripting tool for outbound calling. 
I've seen over 300G an hour of memory allocated with 100 users and we need to support 
well over 200. With that much memory being consumed it obviously garbage collects 
pretty much constantly. A very low percentage of the objects make it to the old 
generation so the young generation garbage collection is crippling the box, 
particularly if it has a busy spell.

I believe a lot of the memory is in the sessions which seem to be a fairly substancial 
size. The app also does a lot of XML parsing and I'm sure there is a little too much 
String concatenation in there as well.

I'm not sure of the load in terms of requests per second but i'd imagine up to 50 but 
more likely an average of 10-20 (this is purely guesswork though).

Currently supporting about 100 users we've had the most success by fixing the eden 
space at 384M and not using the survivor spaces. Using the ParNewGC with 4 threads and 
the CMS collector in the old generation.

Anything else i've missed?


-----Original Message-----
From: Shapira, Yoav [mailto:[EMAIL PROTECTED]
Sent: 13 August 2004 17:58
To: Tomcat Users List
Subject: RE: [OT] - JVM Max Heap Size on Linux


Hi,

Just out of curiosity, what app(s) are you running that need a heap
greater than 2GB?  Or what load on those apps?  You obviously don't need
to give confidential details, I'm just curious about the type of app and
its architecture.

 

Yoav Shapira
Millennium Research Informatics

-----Original Message-----
From: Dale, Matt [mailto:[EMAIL PROTECTED] 
Sent: Friday, August 13, 2004 12:41 PM
To: Tomcat Users List (E-mail)
Subject: [OT] - JVM Max Heap Size on Linux

 

Hi, 

Has anyone got around the maximum heap size of 2G on linux? We've got a
new server with 12G of ram which was going to be used for an uber tomcat
but this plan may have to be changed if we can't get more than 2G of
memory used for the JVM.

Ta 
Matt 

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