Not all subnets are balancing

[Norman Elton]

I should add that this is ISC DHCP 4.1.1-P1, packaged by RedHat
(dhcp-4.1.1-38.P1.el6.x86_64)


Norman

On Thu, Oct 9, 2014 at 4:28 PM, Norman Elton <normelton at gmail.com> wrote:
> I've got two DHCP servers configured for failover:
>
> failover peer "wm-dhcp-01-02" {
>   primary;
>   address 1.2.3.4;
>   port 647;
>   peer address 1.2.3.5;
>   peer port 647;
>   max-response-delay 30;
>   max-unacked-updates 10;
>   load balance max seconds 3;
>   mclt 1800;
>   split 128;
>   min-balance 60;
>   max-balance 300;
> }
>
> I've noticed that our DHCP log file shows helpful information when
> subnets get balanced:
>
> balancing pool 7f9da82e7960 INIT-WM-HALL  total 240  free 88  backup
> 96  lts -4  max-own (+/-)18
>
> But this doesn't seem consistent. That is, there are some subnets that
> balance, others never show up in the log. Presumably there's some
> small difference between the two, but I can't figure it out. Here's a
> subnet that is getting balanced:
>
> group {
>     option subnet-mask              255.255.255.0;
>     option domain-name-servers      128.239.29.9, 128.239.20.9;
>     option domain-name              "wm.edu";
>     default-lease-time              3600; # 1 hour
>     max-lease-time                  3600; # 1 hour
>
>     shared-network INIT-WM-HALL {
>         subnet 10.45.170.0 netmask 255.255.255.0 {
>             option routers                  10.45.170.1;
>
>             pool {
>                 failover peer   "wm-dhcp-01-02";
>                 range           10.45.170.11        10.45.170.250;
>             }
>         }
>     }
> }
>
> And here's a seemingly similar subnet that is never showing up in the log file:
>
> shared-network ADMIN-NET {
>     subnet 128.239.96.0 netmask 255.255.224.0 {
>         option subnet-mask              255.255.224.0;
>         option routers                  128.239.102.1;
>         option domain-name-servers      128.239.29.9, 128.239.20.9;
>         option domain-name              "wm.edu";
>         deny                            bootp;
>         default-lease-time              432000; # 5 days
>         max-lease-time                  432000; # 5 days
>
>         pool {
>             failover peer   "wm-dhcp-01-02";
>             range           128.239.102.10  128.239.102.254;
>         }
>     }
> }
>
> Am I missing something? Is there some reason why the first would
> rebalance and the second not?
>
> Thanks,
>
> Norman Elton