Failover and pools with single machines

[Tina Siegenthaler]

Hi list

We have configured our dhcp server with lots of classes/subclasses/ 
pools that contain but one single host. The reason was that using  
"fixed-address" for assigning fixed addresses to hosts doesn't make  
those hosts appear in the lease file.
Now we'd like to implement failover... but what will happen to those  
pools with just one host? It's difficult to split a range of just one  
IP equally between two dhcp servers, and that's what failover does,  
if I understand it correctly. Can we use failover nevertheless, or  
will we run into problems? What happens when one server goes down?

Example config:

ddns-update-style none;
option domain-name-servers 130.60.128.3, 130.60.64.51;
option domain-name "unizh.ch";
authoritative;
log-facility local1;

# hosts
host PBG4 { hardware ethernet 00:0a:95:e6:xx:yy; }
host CODEC { hardware ethernet 00:50:60:80:xx:yy; }

# classes
class "PBG4" { match pick-first-value (option dhcp-client-identifier,  
hardware); }
class "CODEC" { match pick-first-value (option dhcp-client- 
identifier, hardware); }

# subclasses
subclass "PBG4" 1:0:0a:95:e6:xx:yy;
subclass "CODEC" 1:0:50:60:80:xx:yy;

# subnet 225, lower part
subnet 130.60.225.0 netmask 255.255.255.128 {
         option routers 130.60.225.1;
         option broadcast-address 130.60.225.127;
	pool { allow members of "PBG4"; range 130.60.225.90; }
	pool { allow members of "CODEC"; range 130.60.225.93; }
         pool {
                 allow unknown-clients;
                 range 130.60.225.20 130.60.225.80;
         }
         max-lease-time 21600;
}

Thanks for your help,

Tina