tomcat-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Antonio Fiol Bonnín <fiol.bon...@terra.es>
Subject Re: Réf. : Re: maxProcessors = max ammout of concurrent connections?
Date Fri, 20 Feb 2004 15:44:00 GMT
As far as "connections" does not mean "active connections", what 
"meissa.Sakho" wrote is strictly true.

Each Apache process connects to Tomcat when (if) it needs to. Call that 
a "connection".

Apache processes do not disconnect from Tomcat. Call those "idle 
connections".

idle connections <= connections <= number of Apache processes <= MaxClients

Of course some of the connections are used at a certain moment.

active connections <= connections

But at any moment in time, an Apache process that is not connected to 
Tomcat MAY receive a request, and start a connection to Tomcat. So, it 
is possible (and it actually happens most of the time) that even if your 
Apache is serving static content, all of the Apache processes are 
actually connected to Tomcat.

This means that connections <= MaxClients, with the strict equality 
being possible.


If you have more than one instance of Tomcat, the same thing happens.


An Apache process that is connected to one of your Tomcat servers MAY 
receive a request that has to be processed by your second Tomcat. So it 
will connect to it, without dropping the connection to the first Tomcat.

So maxProcessors >= MaxClients is true for any scenario with Apache and 
Tomcat.

Even worse...

If you have two Apache and two Tomcat,

maxProcessors >= sum(MaxClients) for all your Apache servers.


Otherwise, busy sites experience hangs.




Of course, if you do not use Apache as a frontend, and you simply have a 
load balancer, you can keep maxProcessors much lower.



Yours,


Antonio Fiol







Pepijn Palmans - Kangaroot wrote:

>That is not true.  This can be only true if you have only one instance of
>tomcat, and ALL (even static!!!) content is serverd by tomcat.
>
>Under normal setup you let your static content be served by apache, and
>only use tomcat when needed.  So you might wanna have more apache
>processes.
>
>Pepijn
>
>On Fri, 20 Feb 2004 meissa.Sakho@assetmanagement.natexis.fr wrote:
>
>  
>
>>As I know, the maxProcessor value must match
>>the MaxClients value in apache, because each apache
>>process must connect to a processor in Tomcat.
>>_______________________________________________
>>NATEXIS ASSET MANAGEMENT
>>Meissa SAKHO
>>01 58 19 45 71. . . . . . . . . . . . (84571)
>>meissa.sakho@assetmanagement.natexis.fr
>>    
>>


Mime
View raw message