Deployed applications doesn't respond

[9424419352]

My server is wndows 2003 with Apache tomcat web server. There are many applications deployed to this server. Last one month I am noticing that that none of single application doesn't respond after 24 hrs(approximatle). The tomcat is also in running state during that time.

Solution to this is to restart the Apache Tomcat server. I would like to know why this is happening and what to do for smooth running of the application




Dhruba

[kjkoster]

Dear Dhruba,

When Tomcat hangs, is the cpu usage 0% or 100%? Are there any exceptions in the Tomcat logs?

Are you monitoring that Tomcat server with Java-monitor? If so, you can check the memory, database pool and HTTP connector graphs to see if the HTTP pools are filled up.

Failing that, you can also make thread dumps to find out what your threads are doing. I wrote a few articles on that.

http://java-monitor.com/forum/showthread.php?t=616
http://java-monitor.com/forum/showthread.php?t=317

If you could answer some of the question above we can perhaps help you solve this.

Kees Jan

[9424419352]

Yes, my server is monitoring by java monitor system

Next time when my Tomcat server hang, I will look into the parameter you have mentioned and will post here for solution .

[9424419352]

Dear kees Jan

Today I face the same problem of tomcat hanging. During that time I catured the screen shot java monotoring. The pdf file is captured and attached herewith.
I checked cpu usage is on 4 %

Thanks
Dhruba

[kjkoster]

Dear Dhruba,

I see no attached image. Can you please try to post it again?

Kees Jan

[9424419352]

Dear Kees Jan

Actually size is more of the attachment file .Thats why it is not attahed in the post. I kept the file in our server. You may access through the following link

http://gismp.nic.in/test1/Java-Monitor%20Forum%20-%20Host%20Details.pdf

Every day I am facing the problem of hang out.

Thanks

Dhruba

[kjkoster]

Dear Dhruba,

In your PDF I found some interesting things.

Note how your garbage collectors are working really hard and you have huge GC times. 8 seconds is very slow.

http://java-monitor.com/misc/slow-gc-2.png

On the other hand, there is hardly any memory use.

http://java-monitor.com/misc/slow-gc-2.png

This looks a little like a problem I saw earlier:
http://java-monitor.com/forum/showthread.php?t=173
http://java-monitor.com/forum/showthread.php?t=188

Can you please confirm that your application never calls the GC explicitly? The best way is to use findbugs, but you can also run Tomcat with -XX:-DisableExplicitGC so that the GC call will be ignored.

If that does not help, I have to admit that I have no idea what is causing these problems.

Kees Jan