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From Mark Thomas <ma...@apache.org>
Subject Re: mod_jk makes ajp connector run out of free connections
Date Fri, 05 Nov 2010 17:22:42 GMT
On 04/11/2010 20:01, Marc Wilmots wrote:
> Honestly....no, I didn't.
> The mod_jk scared the hell out of me....wouldn't you? :-)
> 
> "Using this option will have a strong performance penalty for Apache and
> Tomcat. Use this only as a last resort in case of unfixable network
> problems."

Experience has shown that the impact is usually (YMMV) a lot less
significant than that. You're right - we should update the docs.

Mark

> 
> I'll give it a try tomorrow and see what it gives.
> 
> By the way, my last calculation about connection_pool_size was wrong. I
> forgot to include the second Apache server. The math would look like this
> then:
> 
> Apache1 -> 10 server processes x 15 x 4 (tomcats) = 600
> Apache2 -> 10 server processes x 15 x 4 (tomcats) = 600, which makes 1200 in
> total
> 
> Each Tomcat would receive a maximum of 300 connections, which would leave
> 100 free connections per Tomcat. This would solve the problem that Tomcat
> runs out of connections. The thing is...not all of my available Apache
> connections can be used:
> 
> Apache has 60 threads per server process (10) -> 600 connections.
> connection_pool_size per server process: 15. This would mean only 15 of 60
> possible connections per server process can actually establish a connection
> to Tomcat.
> 
> In order to be able to server all Apache connections simultaneously, I would
> need 4 more Tomcats?
> 
> 
> 
> 
> 
> 
> 2010/11/5 Mark Thomas <markt@apache.org>
> 
>> On 04/11/2010 19:27, Marc Wilmots wrote:
>>> The best solution would be to enable DisableReuse as Mark stated,
>> although
>>> I'm afraid that would be too big of a performance hit.
>>
>> Have you tried it?
>>
>> The cost of the required CPING/CPONG isn't that different to the cost of
>> creating a TCP/IP connection. On a fast local area network I doubt you'd
>> notice it. The time taken to establish a TCP/IP connection is usually
>> (YMMV so test it) << the time taken to process a request.
>>
>> Mark
>>
>>
>>
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> 




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