Unintended but successful stress test of DHCP server

[sthaug at nethelp.no]

There have been many questions about the capacity of DHCP servers on
this list. Yesterday, due to an unfortunate series of circumstances,
one of our DHCP servers had what was in practice a significant stress
test. I thought it might be interesting to give a small status.

At peak traffic the server handled the following load per second:

- 500 Discover
- 500 Offer
- 850 Request
- 800 Ack
-  60 Nack

This server is part of a failover pair, and seemed to handle the
communication with the failover partner without any problems. We
believe the server would be able to handle quite a bit more DHCP
traffic, actually.

The server is a HP Proliant DL360, 12 GB memory, 146 GB RAID-1 disk
with battery backed cache, running FreeBSD 8.4-STABLE and ISC DHCP
4.2.5-P1. No significant problems were observed (the insignificant
problems being that all log files etc were of course growing much
faster than we had planned for).

Steinar Haug, Nethelp consulting, sthaug at nethelp.no