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List:       james-user
Subject:    Re: scalability/performance/throughput problems with james 2.3.1?
From:       Stefano Bagnara <apache () bago ! org>
Date:       2008-11-17 21:34:45
Message-ID: 4921E375.1070608 () bago ! org
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Peter Doschkinow ha scritto:
> Hi Stefano,
> 
> many thanks for your explanations which sound quit plausible to me.
> Nevertheless I would like to investigate a bit more if james scales good
> enough for a use cases where heavy email encription/signing is applied.
> How can I tell the proper version of  e.g.
> 
> org.apache.excalibur.thread.impl.WorkerThread.java
> 
> which is obviously bundled with james 2.3.1, is it from excalibur 4.1?

I don't know what is excalibur 4.1

It is from excalibur-thread-impl-2.1.jar, so it should be 2.1.

Stefano

> Thanks and best regards
> Peter
> 
> 
> Stefano Bagnara schrieb:
>> Peter Doschkinow ha scritto:
>>  
>>> Hi Stefano,
>>>
>>> thanks for your fast reply! I swithched now to james 2.3.1 but I am
>>> seeing  only minimal improvements,  maybe 5%.
>>>
>>> What I observe is still too many threads waiting - at the OS level I see
>>> that the LWPs(the light weight processes that the java threads from
>>> james are mapped on) spend most of their time waiting on user
>>> locks(around 80-100%), spending only max 8-12% in user time...
>>>
>>> Asuming that the OS is distributing the java thread well among the
>>> available 40 hardware treads, what would be the best configuration for a
>>> load test on say 25 concurrent smtp client connections in terms of
>>> number of spool threads and max. thread number in the default thread
>>> pool? Can I get somehow rid of the impact of the watchdog-threads?
>>>     
>>
>> I spool around 1 million/mail per day on a small shared server using 50
>> threads, CPU usage is always very low, but disk/network usage is high.
>>
>> In my experience the JVM version and the OS change the performance a
>> lot. I'm on linux 2.6 and the latest jvm 6 now.
>>
>> There is not too much you can "tweak" in james spooling unless you write
>> your own spoolmanager object.
>>
>> And there is not a generic rules for number of threads. Keep in mind
>> that the real world scenario is different from a load test. If you want
>> to make a good load test try to add a lot of
>> wait/sleep/timeout/unexpectedclose in your test connections.
>>
>> E.g: In my server dns lookups are one of the most used resources.
>>
>> Furthermore spooling is disk and network intensive rather than
>> cpu/thread intensive: don't expect to see the cpu to go high unless you
>> have a fast disk/cache and a fast network.
>>
>> Stefano
>>
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>>   
> 
> 
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