Use DHCP Failover

DHCP failover is a feature for ensuring the high availability of a DHCP server. With DHCP failover two DHCP servers share DHCP information so that if one goes down the other server can still provide DHCP leases to clients.

The DHCP failover option is built into the Windows server operating system. The picture below shows the setup of two DHCP servers configured with load balance failure mode. If one server fails the other server is still active and takes over all DCHP requests.

There are two failover design options:

Hot standby design

When using hot standby mode one server is the active server and the other is a standby. The active server is the primary server and handles all DHCP requests. If the active server goes down the standby server takes over the DHCP requests.

This option is commonly used with the standby unit being at a physically different location than the active.

Load balance design

In load balance mode both servers work in an active-active mode to handle DHCP requests. The requests are load balanced and shared among the two DHCP servers. If one of the servers loses contact with its failover partner it will begin granting leases to all DHCP clients.

Summary
You will need to determine which failover design is best for your environment. It’s a free built in option so take advantage of it and make your DHCP servers are fault tolerate.