Jetty is getting stucked during high-load tests

I have a web service composed by 2 Jettys (running the same content) load-balanced by a HA Proxy. During a test that consists in a medium requests per second rate (less than 100) and each request having a big body (21 KB), Jetty gets stucked -- It doesnt respond to any request.

The only way to bring Jetty up is restarting it.

I didn't find any information in log files (2011_05_20.stderrout.log, 2011_05_20.log) -- It seems to stop logging.

There are any other useful log files that I should enable in Jetty configs ?

Have anyone ever experienced this weird behaviour ?

Could I retrieve some info about thread s开发者_JAVA百科tatus from Jetty (I'm not sure if all threads are busy, the request is rejected) ?

Thanks in advance!

How many threads have you specified in jetty.xml ? I think per default (at least for embedded Jetty), the maximum number of threads is set at around 50. You can change this either programatically, or via jetty.xml. Rather than just setting max to a high number, you should figure out a correct value, depending on server resources and load requirements.

<Configure id="Server" class="org.eclipse.jetty.server.Server">
<!-- =========================================================== -->
<!-- Server Thread Pool -->
<!-- =========================================================== -->
<Set name="ThreadPool">
    <New class="org.eclipse.jetty.util.thread.QueuedThreadPool">
    <!-- initial threads set to 50 -->
    <Set name="minThreads">50</Set>

    <!-- the thread pool will grow only up to 768 -->
    <Set name="maxThreads">768</Set>
    </New>
</Set>

</Configure>

Use something like jVisualVM or BTrace to find out how many threads that are in your threadpool. Heres a link to a BTrace script to print out thread counts: https://github.com/joachimhs/EurekaJ/blob/master/EurekaJ.Scripts/btrace/1.2/btraceScripts/ThreadCounter.java