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From Sander Smeenk <>
Subject Re: [users@httpd] Apache 1.3.x as loadbalancer
Date Fri, 30 Apr 2004 21:32:51 GMT
Quoting Leif W (

> > I'm curious as to what performance one might expect from an AMD Athlon
> > 1GHz server functioning as a loadbalancer with RewriteMaps,

> I'm not too familiar with load balancing, or ab, but had some comments.
> Have you checked the statistics of all the balanced servers combined?
> Combined, how many hits do they get in 24 hours?

I indeed did some checks on the current situation, and how much load all
servers currently get. The combined number of requests-a-second-average
from all servers averages at 40 requests a second.
My current loadbalancer can handle 166 requests a second average at max.

That looks promising, until a co-worker of me pointed out that the
'current-requests-being-processed'-rate of all servers combined averages
at 70 with peaks to over 150.

So now i'm confused again wether the 166 requests-a-sec from ab compare
to the requests-a-sec returned by the server-status module, and the
current requests being handled.

> > Would there be a lot of speed-change in wether the RewriteMap
> > program is written in C instead of perl?
> I don't get what you mean, "'perl' only needs to be started once".  It
> gets started once per execution if you're using scripts with "#!
> /usr/bin/perl" in them, and this loads the entirety of the Perl
> translator into memory.

A perl script when used as a RewriteMap starts once and then loops in an
endless loop waiting for data on STDIN that it then processes and prints
out a new URL on STDOUT. I am 100% certain the RewriteMap program does
not get started for every request made.

But this 'problem' is fairly easy to solve by having the same
configuration run a test with a perl script and do the same with an
equivalent C program, so it's not really relevant at this point. I might
as well not have asked it ;)

Thanks for all your tips, I will certainly work on them next monday.

> > | You dig around for a while but you fail to find any treasure.
> P.S. Looking for a golden pobble bead?  If not, I thought it was in
> reference to a game...  ;-)

It is in reference to a game :)
The best game I ever played: Ultima Online.

Kind Regards,
| Showering in clothes shows you're crazy. Showering nude shows your nuts.
| 1024D/08CEC94D - 34B3 3314 B146 E13C 70C8  9BDB D463 7E41 08CE C94D

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