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From "Howard W. Smith, Jr." <>
Subject Re: Help in diagnosing server unresponsiveness
Date Fri, 01 Feb 2013 03:58:25 GMT
On Thu, Jan 31, 2013 at 10:32 PM, Zoran Avtarovski
<> wrote:
> 1.The app has been running on Tomcat 7 in a virtualised linux environment
> for about 4 months and the issue has been persistent through that time.
> Prior to that it was running on a physical Windows server with no issues.
> The move to linux coincided with the addition of a substantial amount of
> WebServices functionality - consuming.

very interesting, stable on windows (without webservices footprint).
what was your java -version details on windows, and what is your java
-version details on linux?

so the webservices functionality is 'new' software/code? was the code
implemented well for GC? any use of threadlocals? i am only shooting
from the hip, here, as I primarily listen in on topics here, and have
limited experience with java and tomcat.

> 2.The tomcat instance was originally running with a max of 6Gb of
> allocated memory and it would crash almost daily. When we upped it to 11gb
> the crashes reduced to about twice a week.
> 3. Tomcat is configured with the following options export
> JAVA_OPTS="-Xms256m -Xmx11460m -Djava.awt.headless=true
> -XX:MaxPermSize=256M -XX:+CMSClassUnloadingEnabled
> -XX:+UseConcMarkSweepGC"
> 4. Xms and MaxPermSize were just reduced from 512m
> 5. The app generally has about 50-100 concurrent users - the logs show
> that Tomcat can crash with as few as 20 users. I'm wondering if it could
> be GC related as the crashes often follow periods of heavy use.
> 6. The app is a struts2 based app using Spring 3.5 for dependancy
> injection/ioc.

this is good to know. have you seen/heard of similar reports from
others using struts2 and spring 3.5 for dependancy injection/ioc?

> The problem with getting a thread dump is that high CPU usage is only a
> spike and server freezes. CPU usage only goes above 5-10% when it's about
> to crash. Support then reboot the server instances and off it goes. I've
> tried to spend a few days just watching, but of course it didn't skip a
> beat while I was monitoring. Is there a way to trigger gather relevant
> data when Tomcat crashes?
> Z.

I searched tomcat user list, please see below, and consider what was
mentioned there for troubleshooting this issue, and report back here.

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