Balance the load on your DHCP servers by using the 80/20 rule for scopes
Applies To: Windows Server 2008 R2
You can use the 80/20 design rule for balancing scope distribution of addresses where multiple DHCP servers are deployed to service the same scope.
Using more than one DHCP server on the same subnet provides increased fault tolerance for servicing DHCP clients located on it. With two DHCP servers, if one server is unavailable, the other server can take its place and continue to lease new addresses or renew existing clients.
A common practice when balancing a single network and scope range of addresses between two DHCP servers is to have 80 percent of the addresses distributed by one DHCP server and the remaining 20 percent provided by a second.