dhcp 3.0.5 crashes with lots of lease imbalance messages

[K. K. Tam]

Hi,

Our site is running dhcp 3.0.5 in failover and the primary and secondary 
servers are with CentOS 4.
The service has been very stable since its rollout in 2007.  A few 
months ago, we have set up a few
IP pools with relatively short lease time from 15 minutes to 30 
minutes.  Then the dhcpd in the
primary server would crash from time to time with lots of "lease 
imbalances - lts" messages as
below.

Dec 11 01:33:55 <hostname> dhcpd: lease imbalance - lts = 23
Dec 11 01:33:55 <hostname> dhcpd: lease imbalance - lts = 17
Dec 11 01:33:55 <hostname> dhcpd: lease imbalance - lts = 3

The number of these messages ranges from 800 to 1000 before the daemon 
crashes.  It is observed
that crash happens as the usage in these pools increases.  The MCLT in 
our set up is 1800.  Our
current workaround is to extend the lease time of these pools to 30 
minutes and 2 hours with
the trade off of IP usage.  The situation improves a bit but still has 
crashes from time to time.
The worst case we had before extending some to 2 hours lease time was 
crashes around every 5 to
10 minutes for the whole afternoon till the usage slowed down.  We have 
about 12000 available
IPs and the active usage is around 60%.

I have searched the archive of the mailing list and the problem happened 
for some previous version
yet there was no concrete solution.  I wonder if anyone can provide some 
suggestions or solutions for
this problem.

Thanks in advance.


Regards,
K. K. Tam

Email: k.k.tam at ust.hk