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From Antonio Fiol BonnĂ­n <fiol.bon...@terra.es>
Subject Re: Production server tuning
Date Wed, 30 Jul 2003 18:04:30 GMT
Bill Barker wrote:

>In theory, I'd go with Kwok's recommendation:  one Apache with it's own
>load-balancer, and 3 Tomcats instead of 3 Apaches.  However, in the
>real-world, this would require you to upgrade to Apache 2.0.x with the
>'worker' MPM.
>

We cannot repurpose machines. Three web servers (a fourth one is in the 
way, don't ask why) are a need for other projects, as Apache servers are 
shared. And technically, I don't think it is viable either (see previous 
post).

However, I am worried about what you say about Apache 2.0.x and the 
'worker' MPM. Could you please tell me about the real-world 
inconveniences of having 3/4 Apache 1.3.X with 2/3 tomcats behind?


>Yes, for your current config, you need to have your maxProcessors somewhere
>near 600 to handle peak load.  For part two, go to each of your Apache
>machines and run:
>  $ ps -ef | grep httpd | wc -l
>

Done that. Very varying, depending on time of day. But we set MaxClients 
to 200 knowing what we were doing. We used to have 100 and it was not 
enough. Raised to 150 and still not enough. It was during a peak period, 
but I don't think we should lower it back.



>Add the numbers together, and subtract three (one for each of the Apache
>'controller' processes).  If the system has been running for awhile, this
>should be about the same as the number of connections to your Tomcat server
>on 8009, since mod_jk holds the connection open (by default) for the
>lifetime of the Apache child.
>
The problem is that the connection is kept open even if unused, isn't it?

I mean: If I do not connect to my web-app, does it start the connections?

>  The threads that are waiting for Apache to
>talk to them are blocked pending input, so aren't affecting Tomcat's
>performance in any way.
>
Except maybe memory requirement??


>Since you are using 4.1.9, I'm assuming that you are using the AjpConnector
>(instead of the newer CoyoteConnector).
>
I think it is CoyoteConnector, but I'd have to check to be sure.

We'll be moving to 4.1.26 as soon as we have time to test our app on it. 
Stuck on 4.1.9 because of client cert auth problem.


> With the AjpConnector, you can set the attribute
>'connectionTimeout=xx-ms"' to have Tomcat drop the connection to Apache
>after xx milliseconds have gone by without traffic.
>
Does that apply to CoyoteConnector? Is it really useful?

>For tuning, I like OptimizeIt (but it costs).
>
It helped me once upon a time. But I'm in a different company now.

>  I'm sure that other people
>will offer there opinions.
>
Yes, I heard of JProbe. Never tested. Any insights? How is it compared 
to (3 years ago) OptimizeIt?


Thank you very much for your answer, Bill. I think it was really useful.


Antonio Fiol

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