If you use Microsoft DHCP in your environment, check out our guide about a great new feature in Windows Server 2012 for enabling high availability for DHCP services: Understand and Deploy DHCP Failover.
DHCP failover enables you to share IPv4 scope settings and leases between two DHCP servers, and provides another option for high availability in addition to split-scope and clustered DHCP.
DHCP failover in Windows Server 2012 is based on the IETF DHCP Failover Protocol draft, but Microsoft's implementation is unique.
The guide includes concepts, specifications, and requirements for deploying DHCP failover as well as detailed steps to begin using DHCP failover. Enjoy!
Technical Writer, Windows Server