Chris,
thanks for this, we just had an un-configured default connect.
thanks
Tim
On 1 July 2010 17:11, Chris Wareham wrote:
> On 07/01/10 16:44, Sad Clouds wrote:
>>
>> On Thu, 1 Jul 2010 16:16:13 +0100
>> Tim Pizey wrote:
>>
>>> The last message, from Nagios was:
>>>
>>> CRITICAL - load average: 9.11, 7.26, 3.76
>>>
>>> so it was getting hit pretty hard.
>>> It was only a 1gig VM. I EC2 is based on Xen.
>>
>> Does Java have some sort of event notification framework, i.e. epoll,
>> kqueue, etc? What usually bogs down Java applications is the number of
>> threads they spawn. So if Java/Tomcat creates a thread for each new
>> connection, pretty soon you'll end up with no memory.
>>
>> Assume 4 MB for a thread stack, 192 * 4 = 768 MB. If you were using an
>> event loop to multiplex different sockets, you could scale this much
>> higher.
>>
>> For example, I have a simple network test application that uses kqueue.
>> At 1000 requests per second, 1 GHz Pentium 3 CPU is 40% busy and memory
>> overhead is pretty small.
>>
>
> You can configure an "Executor", which is a thread pool with a hard
> limit on the number of concurrent threads in the pool. On my test
> system we have the thread pool configured to max out at 500 - when
> thrashed by JMeter running on a separate machine over a gigabit
> ethernet connection, the server copes without locking up (our servers
> have a 3.2GHz Xeon and 4GB of RAM).
>
> Tim - what do your Executor and Connector configs look like? On our
> machines they are setup as follows (key stuff anonymised):
>
> <Executor name="thread.pool"
> maxThreads="500"
> minSpareThreads="50"
> maxIdleTime="30000"/>
>
> <Connector port="8080"
> proxyPort="80"
> redirectPort="8443"
> executor="thread.pool"
> acceptCount="100"
> connectionTimeout="10000"
> keepAliveTimeout="10000"
> maxKeepAliveRequests="75"
> disableUploadTimeout="true"
> enableLookups="false"
> compression="on"
> URIEncoding="UTF-8"/>
>
> <Connector port="8443"
> proxyPort="443"
> executor="thread.pool"
> acceptCount="100"
> connectionTimeout="10000"
> keepAliveTimeout="10000"
> maxKeepAliveRequests="75"
> disableUploadTimeout="true"
> enableLookups="false"
> compression="on"
> URIEncoding="UTF-8"
> keyAlias="********"
> keystorePass="********"
> scheme="https"
> secure="true"
> SSLEnabled="true"/>
>
> Chris
> --
>
>
>
>
> Chris Wareham
> Senior Software Engineer
> Visit London Ltd
--
Tim Pizey
Centre for Genomics and Global Health <
http://cggh.org>
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