DHCP/UDP performance tuning..

[Bruce Hudson]

> Mathematically I'm figuring that the server should be getting about 24
> requests per second. This is figured out with 47110 current leases with a
> 7200 sec default lease time with a 14400 max-lease.  Additionally I have 531
> leases that have a 30 sec lease time.  Since we use a MAC address
> registration system the pool with the 30 sec leases are for unregistered MAC
> addresses.

    To start, your math is wrong. Remember that with a 30 second lease, a
client will renew every 15 seconds (at the half-way point for another 30
seconds). Assuming nobody specifies a lease period, your 47110 clients,
renewing once an hour will generate 13 requests per second. The actual
number will probably be closer to twice that since I supsect your maximum
lease time will dominate. Your 531 clients, renewing every 15 seconds
generate 35 requests per second; by far the dominant load. 

    I would serious reconsider your 30 second leases. Even the 2-4 hour
leases are fairly severe. What do you gain from keeping your leases this
short? Are your pools so small they cannot handle the address churn if
they are longer?
--
Bruce A. Hudson				| Bruce.Hudson at Dal.CA
UCIS, Networks and Systems		|
Dalhousie University			|
Halifax, Nova Scotia, Canada		| (902) 494-3405