Dear Chris,
We've been running into some issues lately with our Tomcat 6
instances where performance will slow to a crawl. Unfortunately, no
error messages are present in the logs and we really don't know why
this is happening. It does appear that the issue is happening when
we get "a lot" of users on the system at one time. It would make
sense, but we're only talking about 300 or so concurrent users.
There must be a point of misconfiguration on our part but none of us
really have any experience with Tomcat outside of simply setting it
up and running it out of the box, which isn't much. So, that leads
me to why I'm posting to the user list:
1. Are there any tools or utilities we can use to get an
understanding of what Tomcat is doing while it's running (processes,
memory per process, and more)?
VisualVM, JConsole, Java-monitor.com, many commercial tools.
2. I suspect there are some very large Tomcat installations out
there. Has any information from those installations been
published? Is there a guide or set of documentation on how to scale
with Tomcat as a web server?
There is a lot of documentation, but more on tuning Java, rather than
Tomcat. Tomcat has surprisingly few tunables that get mentioned on
this list. It is pretty lightweight in the sense that there is not a
whole lot of Tomcat going on between you and an incoming HTTP request.
Most likely, if you tune the underlying VM to your workload, your
problems go away (or move to a place that is not your jurisdiction).
Perhaps we can help?
What is your machine doing when Tomcat is slow? Network/disk I/O-
bound? CPU-bound? What percentage is your machine spending in system
time, as opposed to user time?
--
Kees Jan
http://java-monitor.com/forum/
kjkos...@kjkoster.org
06-51838192
The secret of success lies in the stability of the goal. -- Benjamin
Disraeli
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