MaxClients value when Apache is used with Tomcat backend

Hello to everyone!

Firstly, I would like to apalogize for this beginner's type of question but I am quite new to the web servers' world. In the IT environment I am working we have an Apache web server which is used as a load balancer to forward incoming requests to two tomcat servers via the AJP protocol. All the three servers are hosted in three different machines. We use tomcat 5.5.20 and Apache 2.0.59 on HP-UX machines.

Below you can find the httpd.conf settings we have for apache:

<IfModule worker.c>
StartServers 8
MaxClients 800
MinSpareThreads 50
MaxSpareThreads 100
ThreadsPerChild 25
MaxRequestsPerChild 0
</IfModule>

and for each tomcat server in server.xml:

<Connector port="8052"
enableLookups="false" redirectPort="8443" protocol="AJP/1.3"
maxThreads="400" minSpareThreads="50" maxSpareThreads="100"
minProcessors="50" maxProcessors="400"
connectionTimeout="600000" bufferSize="60000" />

First question:

When we change the MaxClients value in httpd.conf of apache conf directory, do we have to recompile Apache? Because currently we only use:

apachectl -k start

to restart it. At the same time I do not understand well the MaxClients value. We have a worker MPM environment and I have read that the MaxClients value of Apache is the maximum number that this value can reach:

ps -ef | grep httpd |grep -v grep | wc -l

Is this true? If it is true then why the following two numbers are different in the apache macine? (apache listens to the port 8082)

ps -ef | grep httpd |grep -v grep | wc -l
netstat -na | grep 8082 | wc -l

Actually the number of connections seen from the last command (netstat -na | grep 8082 | wc -l ) is always greater than the number of httpd processes (ps -ef | grep httpd |grep -v grep | wc -l). Is it possible that a single httpd process serves more than one connections on 8082 port? Do we also have to change the ServerLimit value when chaning the MaxClients value?

Our Apache server talk with the two tomcat servers via the 8052 port in the machines where the two tomcats reside. But when we give the following command on the apache machine:

netstat -na | grep 8052 | wc -l

then we see a huge number of connections (e.g. 600) when at the same time the following command:

netstat -na | grep 8082 | wc -l

shows there are only 110 connections to the apache 8082 port (from the outside world). How is this difference possible?

Any help would be higly appreciated!

 

I believe the proper syntax is "apachectl -k restart"
Yes, you need to reload apache after making a configuration change.

The problem with the connections below could be the timeout values. How many TIME_WAIT vs. ESTABLISHED connections do you see?