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From Edoardo Causarano <edoardo.causar...@gmail.com>
Subject Re: Clustering with mod_jk
Date Fri, 01 Sep 2006 19:54:36 GMT
Using mpm_worker gave less impressive results; I'd say about 1/2, a  
much worse load average (way more than 5), and lots of swap. Seems  
like prefork works better on linux and I'm surprised. Anyway,  
assuming that I got the maxProcessors wrong I should have seen queues  
building up @ 150*4 instead they start < 50% that value.

The thing that makes me think it's a mod_jk issue is the fact that  
suddenly all request flow locks onto a node and stays busy until I  
restart apache.

e

On 01/set/06, at 21:21GMT+02:00, Filip Hanik - Dev Lists wrote:

> since you are using prefork, you must set cachesize=1 for your  
> workers.properties file.
> However, you have 4096 MaxClients, in order to serve this up in  
> tomcat, your JK connector should have maxProcessors="4096".
> An alternative, and safe solution, although much less performance,  
> is to set "MaxRequestsPerChild 1", this way you can get away with  
> MaxClients 4096 and still have a much less maxProcessor value on  
> Tomcat
>
> Filip
>
>
> Edoardo Causarano wrote:
>> Hello List,
>>
>> scenario:
>>
>> - 4 node tc 5.0.28 vertical cluster ( :-| same server... still  
>> testing, but it could have been 8) listening on ajp
>> <Connector address="x.x.x.x" port="8009"
>>     maxProcessors="150" minProcessors="50"
>>     protocol="AJP/1.3"  
>> protocolHandlerClassName="org.apache.jk.server.JkCoyoteHandler"
>>     redirectPort="8443">
>>
>> - 1 httpd 2.0.52 with mod_ajp 1.2.15 and prefork config on RH AS4,  
>> kernel 2.6.9-5.EL
>>     sticky sessions are disabled to avoid stress scripts hitting  
>> only one node
>>
>> <IfModule prefork.c>
>>     StartServers       40
>>     MinSpareServers    80
>>     MaxSpareServers    280
>>     ServerLimit        4096
>>     MaxClients         4096
>>     MaxRequestsPerChild  4096
>> </IfModule>
>>
>> - 1 application where a couple of thousand users should hammer the  
>> app deployed on the webapp
>>
>> What happens is the app takes the stresser for a ride until 240  
>> circa users then starts to die; jkmonitor sees linear increase on  
>> busy and max requests on only one node and pages hang; disabling  
>> the node moves the hung request handling to the next node.
>>
>> Where's the bottleneck? Any known bug in mod_jk? Should I increase  
>> threads on the tomcat nodes?
>>
>> Tnx,
>> e
>>
>>
>>
>>
>>
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>
>
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