my webserver is 3000+ with maxtor sata2 200GB
using debian+apache2+php4+mysql
it's ok when there are not too many connections.
however, when there are around 60 connections,
it takes around 10 sec to load a 10KB webpage.
at that time, the average upload is 30 KB/s only
but normally, my max upload can up to 1MB/s
the cpu usage is only around 1x%
and when I ssh to my server, it's connected without waiting a sec.

so why my web server is running so slowly when there are around 60 connections? is it the problem of my apache's setting?

This my be related to your upload connection rather than anything to do with the server itself. Depends largely on what your connection is, which you have not specified. If you have no load balancing on the server then the server will hand back on a first come first serve basis and the service will degrade. i.e. this is a bandwidth problem. Without concrete details I am guessing.

The connections refer to the number of visitors browsing the webpages from the web server.

my upload bandwidth can up to 1 MB/s on average.
But it's only 1x KB/s when the web server is running so slowly
(i.e. there are more than 60 visitors on the webpages)
Btw, how can I set the load balancing on the server?

Thanks.

This tutorial will give you the reasons why this is happening and how to resolve the situation. I would also look at mod-gzip for apache which compresses responses and speeds up communication significantly.

How have you tweaked your httpd.conf? Have you considered lighttpd?

cg

Are you having a bottleneck at disk access? How is the memory situation on the webserver? (available and swap used)

Thanks everyone!

Finally, I solved the problem by changing the setting of prefork module
<IfModule prefork.c>
StartServers 5
MinSpareServers 25
MaxSpareServers 75
MaxClients 20 <-- changed into 256
MaxRequestsPerChild 0
</IfModule>

I'm glad that you got it to work, and thanks for sharing your solution to help others!