peer holds all free leases

Aug 22 10:31:31 ns1 dhcpd: DHCPDISCOVER from 00:02:b3:c2:10:c2 via
172.27.11.1: peer holds all free leases

> To my mind there is no other value than 128 (half the load) possible. Has
> something changed?

No...

The split statement

split index;

The split statement specifies the split between the primary and sec-
ondary for the purposes of load balancing. Whenever a client makes
a DHCP request, the DHCP server runs a hash on the client identifica-
tion. If the hash comes out to less than the split value, the pri-
mary answers. If it comes out to equal to or more than the split,
the secondary answers. The only meaningful value is 128, and can
only be configured on the primary.

The 'split' value actually isn't the result of a hash.

Instead it decides how many bits are set in a 256 bit buffer.

An index into this buffer is derived from the load balance algorithm.

If the indexed bit is set, it's the primary's, if the index bit is not
set, it's the secondary's.

So, to set all bits in the index to the primary's responsibility, you
configure a split of 255.

Which is equivalent to what the documentation specifies.

By "the only meaningful value", the documentation is trying to steer
people into configuring a 50/50 split. Configuring the service so that
only the secondary responds, for example, is with the current failover
sources a bad idea that's best avoided (it can lead to address
starvation).