Recommendation for redundancy

[Simon Hobson]

Tiago SR <listas at tiagosr.com> wrote:

> If you make use of DHCP Relay or can implement it, you could get the servers failover by VRRP, IP SLA, OSPF, etc.
> The DHCP Relay would query a DHCP Server IP address that would automatically point to secondary server in case of primary going down.

The problem with that is that unless you use the failover protocol then you cannot easily have a seamless handover - this is NOT a stateless server like a web server serving static pages. The standby server must AT ALL TIMES have a completer and up to date copy of what the master server has - that is not easy to do without using failover. If the backup server does not have a complete and accurate copy of the primary server's lease database then you will suffer from one or more potentially serious problems.

Once you use failover to manage syncing the leases to the backup, then you might as well just use failover to manage availability.