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I am a litle bit lost here.

I am using a grails application deployed in tomcat with memcached-session-store. That it uses spymemcached.

I am also using melody plugin to monitor the app.

In the righter-upper part, there is a http-sessions graph that only grows.

We need to know if this is a potential problem. For now, and without know, we daily restart the webservers. And as a last test we are going to let the http-sessions grows to see if in the future it tends to clean it self.

This is the graph that I am talking about:

too many Http sessions

So: is a problem? Do I have to configure memcached, tomcat, grails, memcached-session-store or spymemcached to expirate the sessions with a less expiration time? I couldn't find in Interet how to do that.

Any pointer would help.

thanks in advance

user2427
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1 Answers1

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AFAICS there were 117 concurrent sessions at max, which are not too many generally. You can also limit the maximum number of active sessions in your context.xml/server.xml via maxActiveSessions for the manager btw.

Some questions:

  • Do you experience any issues (e.g. running out of memory or anything else)?
  • How much memory is available to your jvm?
  • How much memory is used by the jvm?
  • Do you know how many sessions your app can handle?
  • What's your session expiration?
  • What's the size of your (serialized) sessions? You can e.g. check jmx stats from memcached-session-manager (see JMXStatistics).

Finally I'd say that you should keep your tomcats up and running until you experience any real problem.

MartinGrotzke
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  • Thanks for the several pointers. There is no issues till now. The memory it seems stable. The session expiration (in $CATALINA_HOME/conf/web.xml) is 10 minutes. I read the section with JMXStatistics but I don't know how to query them by console (the only way I can access the webservers). Do you know how? regards – user2427 Mar 14 '11 at 14:18
  • @damian Good to hear that there are no issues. Regarding jmx, what about http://code.google.com/p/jminix/ (haven't tried it by myself)? This one provides also useful links: http://stackoverflow.com/questions/1751130/calling-jmx-mbean-method-from-a-shell-script – MartinGrotzke Mar 14 '11 at 20:34