performance issues with 4096 subnets

Campbell.ColinD at Campbell.ColinD at
Fri Aug 10 00:45:50 UTC 2012


I'm seeking some guidance. I'm running RHEL5 with dhcpd-3.0.5 (probably
a bad start :-).

We have a requirement to subdivide:

a) into 32k subnets, each a /24 with 4 pools in each subnet
b) into 4k subnets, each a /21 with 1 pool in each subnet

So far we've only attempted (b). The results are less than impressive.

1. A "configtest" takes approximately 90 minutes.
2. The daemon takes approximately 90 minutes to start.

All the time seems to be taken allocating memory for all the addresses.
The process grows to about 2.5GBytes. 

Will moving to RHEL6 with dhcpd-4.1.1 fix this slow start problem?

The server has dual hex-core CPUs and 40GB RAM. 

Colin Campbell
Security Specialist
Public Safety Network Management Centre
p: (07) 3008 4851
f: (07) 3008 4799
e: campbell.colind at

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