I have Tomcat installed & running fairly happily on the mainframe. At times, I see quite a few EXCP's done by Tomcat. I think that maybe my classpath's are not set optimally. I seem to recall there is a way to see what the search order is for classes?
I have tried all kinds of options in Server.XML and am getting nowhere. Appreciate any help!
Thanks,
Nalini Elkins
Inside Products, Inc.
Many EXCPs with Tomcat
Are you seeing excessive EXCPs at startup? This would probably be classloader stuff. If the EXCPs are happening later, after the container and web applications are initialized, then it might be something else.
What EXCP rate are you seeing that concerns you?
The following Tomcat document explains how its classloaders are set up:
http://tomcat.apache.org/tomcat-5.0-doc ... howto.html
You might try googling "Tomcat tuning" to fine more help on tuning Tomcat. One suggestion is to only configure the webapps that you really need. Default apps like "balancer", "web-dav", "samples", etc you can probably remove.
Also, remember that if you are running z/OS under FLEX/ES (as we do), that the Java JVM really performs poorly
What EXCP rate are you seeing that concerns you?
The following Tomcat document explains how its classloaders are set up:
http://tomcat.apache.org/tomcat-5.0-doc ... howto.html
You might try googling "Tomcat tuning" to fine more help on tuning Tomcat. One suggestion is to only configure the webapps that you really need. Default apps like "balancer", "web-dav", "samples", etc you can probably remove.
Also, remember that if you are running z/OS under FLEX/ES (as we do), that the Java JVM really performs poorly
This tomcat is running on a real system. When I first bring it up there are about 150,000 excps.
What I did was just bring Tomcat up and do nothing. Left it running all night long and in the morning there were over 6 million EXCPs. I did not even log on to our application or ANY application. What I am thinking is that somehow there must be some background process in Tomcat which is looking for work to do?
I have been googling Tomcat Tuning & quite a few other things to get some ideas. I think that there is a book on Tomcat at Amazon I have heard about. I can play with the number of active or concurrent threads.
Does your tomcat do this kind of thing?
What I did was just bring Tomcat up and do nothing. Left it running all night long and in the morning there were over 6 million EXCPs. I did not even log on to our application or ANY application. What I am thinking is that somehow there must be some background process in Tomcat which is looking for work to do?
I have been googling Tomcat Tuning & quite a few other things to get some ideas. I think that there is a book on Tomcat at Amazon I have heard about. I can play with the number of active or concurrent threads.
Does your tomcat do this kind of thing?
No, I haven't noticed this behavior. A suggestion would be to start Tomcat without any webapps (at all) and let it run... to see if it uses an IO. That way, you can tell if it is the container itself, or one of the webapps. If no problem found with an empty container, then try adding in the webapps until you find which one is doing the IO.
12 million I/Os per day for our Tomcat
It looks like my system is similar. We are running Tomcat and are using it for cruisecontrol. Started Tomcat on 23Nov and as of now it has 110 million EXCPs indicated in SDSF. That's about 12 million I/Os per day. I generally only look at the cruisecontrol builder results once in the morning, very little activity.
www
www
You don't need the JZOS webapp... is just some examples/samples.
When I start a default Tomcat 5.0.28 configuration, I have the following web apps running: (login to the /manager application to see)
/
/admin
/balancer
/jsp-examples
/manager
/servlets-examples
/tomcat-docs
/webdav
It takes less than 200,000 EXCPS to start everything. I never noticed if an "idle" instance with these apps running would continue to consume IO, but I never really payed much attention, so it could be happening. So, I stopped everything -except- manager and see if the system uses any resources.... after a half hour it was up to 300,000.
Try this on your system... It could that one of the default applications is occasionally doing a bunch of stuff. Or, maybe the Catalina container itself is doing it. I know that the container by default does look in the file system for changes that would cause it to deploy/undeploy applications. Maybe that's the cause.
When I start a default Tomcat 5.0.28 configuration, I have the following web apps running: (login to the /manager application to see)
/
/admin
/balancer
/jsp-examples
/manager
/servlets-examples
/tomcat-docs
/webdav
It takes less than 200,000 EXCPS to start everything. I never noticed if an "idle" instance with these apps running would continue to consume IO, but I never really payed much attention, so it could be happening. So, I stopped everything -except- manager and see if the system uses any resources.... after a half hour it was up to 300,000.
Try this on your system... It could that one of the default applications is occasionally doing a bunch of stuff. Or, maybe the Catalina container itself is doing it. I know that the container by default does look in the file system for changes that would cause it to deploy/undeploy applications. Maybe that's the cause.
Last edited by dovetail on Sun Dec 04, 2005 12:50 pm, edited 1 time in total.
OK, I think I found what was using IO on an "idle" system.
I changed the conf/server.xml, and set autoDeploy="false" on the Host definition.
Then I restarted Tomcat, and from "/manager" stopped all applications except "/manager". The EXCP count now seems to be frozen. It also seems to be using zero CPU cycles.
Apparently it takes some IO to continually check the file system to see if there are new applications to deploy
Regards,
Kirk Wolf
I changed the conf/server.xml, and set autoDeploy="false" on the Host definition.
Then I restarted Tomcat, and from "/manager" stopped all applications except "/manager". The EXCP count now seems to be frozen. It also seems to be using zero CPU cycles.
Apparently it takes some IO to continually check the file system to see if there are new applications to deploy
Regards,
Kirk Wolf