Subject: Two copies of Apache running on the same server...

From: "Yu, Ming" <[email-masked]>
Date: Mon, 24 Jun 2002 11:20:58 -0400

I have a web environment that support both http and https on the same
machine.  The machine is a powerful SParc 450 with a lot of memory and CPU
power.  I am wondering if I can install copies of apache on the same
machine, one runs http, and another runs https.  Will this improve the
server performance?

- Ming 
- System Engineer 
- APL
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From: "Peter Viertel" <[email-masked]>
Date: Mon, 24 Jun 2002 17:08:05 +0100

you can run as many instances of apache that your system can support so 
long as no two instances listen on the same port - at least thats the 
theory.
In practice, apache writes to various files such as the .pid file, 
lockfiles, mutex lockfiles etc - and it can be difficult to make sure 
the different instances dont run into each other. (and remembering this 
each time you compile a new version).

On the other hand, it's just not necessary usually to run multiple 
instances - one apache instance can server http and https on multiple 
ports at the same time using VirtualHost stanzas.

You've probably noticed that apache pre-forks several copies of itself, 
and its these children that handle connections in a parallel fashion and 
go some way to taking advantage of multiple CPU's, but it's not the 
absolute best possible - that would be if you were using solaris 
threads. As it happens Apache 2 is multi-threaded, yet still supports 
pre-forked children, so you can tune it up a lot better.

On the balance of things, I feel it would be harder to get good 
performance out of a system if you used two separate apaches, than if 
you worked on tuning it up with just one.