[Techtalk] calculating server load capability

[Val Henson]

On 4/23/06, Hamster <hamster at invisiblepixels.org> wrote:
> Hi,
>
> Can anyone offer any advice on how to go about calculating what a
> given server's capacity it for performing certain tasks?
>
> I know that software like MySQL and Apache has various stress tests
> that you perform, but I'm after something slightly different.
>
> For example, given a server with a certain processor, RAM, network card
> and acting as a DHCP server, is it possible to calculate any theoretical
> limit as to how many DHCP requests it can handle over a given time?
>
> If you have the scenario where a bunch of clients all get switched on
> at the same time and start asking for an IP, I need some sort of
> indication as to whether a specific server setup can handle in the
> order of 1,000 clients, 10,000 clients, 50,000 clients etc.
>
> If anyone has any ideas or suggestions they would be gratefully
> received.

You can compute an upper limit by running (as root on another machine):

# ping -f -c <number you care about> <dhcp server>

This will tell you a minimum amount of time that it would take to
process that many packets.  But other than that, you'll just need to
run experiments.  You can compute upper and lower limits, but it's
much much harder than just trying it.

-VAL