use of StartServers & MinSpareThreads.

[sunil]

Can anyone help me understand that StartServers and MinSpareThreads, as during my testing I didn't find it useful.

<IfModule prefork.c>
StartServers 8
MinSpareServers 10
MaxSpareServers 25
ServerLimit 100
MaxClients 50
MaxRequestsPerChild 4000
</IfModule>

After restarting, I get the following:

1 requests currently being processed, 10 idle workers.

Not sure why the total workers are 11.

Now when I test using ab -n 300 -c 300 http://192.168.1.3:80/index.php, the total worker exceed to 50 which is OK.

50 requests currently being processed, 0 idle workers

After the test is complete, to again reduced to 25, which is again correct as per MaxSpareServers.

1 requests currently being processed, 24 idle workers


Now I am not sure about:
1) as said above "Not sure why the total workers are 11." when "StartServers 8" and "MinSpareServers 10".
2) role of StartServers & MinSpareServers parameter.
3) I didn't find any benefit of high value for ServerLimit. So, I think value of MaxClients and ServerLimit should be same. Need your comments with reason.