DHCP failover not balancing
Michael Robbert
mrobbert at mines.edu
Wed Aug 20 17:22:16 UTC 2008
I have got a problem with my DHCP servers(3.1.1b1) that are setup with
failover. The initial problem looked like this:
DHCPDISCOVER packet is sent and is recieved by both servers. Primary
says "load balance to peer" and Secondary says "peer holds all free
leases". No lease is given and user can't get on the network. Upon
investigation I have found that the pool messages logged on each server
do not agree with each other. For the pool in question it looks
something like this:
Primary server:
Aug 20 09:17:04 primary dhcpd: balancing pool 8123240 1.2.3/22 total
949 free 206 backup 382 lts -88 max-own (+/-)59
Aug 20 09:17:04 primary dhcpd: balanced pool 8123240 1.2.3/22 total
949 free 206 backup 382 lts -88 max-misbal 88
Secondary server:
Aug 20 09:17:04 secondary dhcpd: balanced pool 8123178 1.2.3/22 total
949 free 588 backup 0 lts -294 max-misbal 88
Aug 20 09:17:04 secondary dhcpd: balancing pool 814e9f0 1.2.3/22 total
30 free 19 backup 0 lts -9 max-own (+/-)2 (requesting peer rebalance!)
Our setup has been running without problems for some time now, but I
have always noticed that lts values are quite often much greater or less
than 1, which according to my reading should not happen on a regular
basis. This is a university campus so the problem has reared its head
now that students are back on campus, but this was working fine last
spring. Here are the basics of our failover setup:
failover peer "primary-secondary" {
primary;
address 1.2.3.2;
port 520;
peer address 1.2.3.3;
peer port 520;
max-response-delay 30;
max-unacked-updates 10;
load balance max seconds 3;
mclt 1800;
split 128;
}
failover peer "primary-secondary" {
secondary;
address 1.2.3.3;
port 520;
peer address 1.2.3.2;
peer port 520;
max-response-delay 30;
max-unacked-updates 10;
load balance max seconds 3;
}
What can we do to get these pools balanced?
Thanks,
Mike Robbert
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