dhcp server on cluster best practices

[Simon Hobson]

José Queiroz wrote:

>I configured these machines to work on failover 
>mode, so each cluster node is a failover peer.
>
>The problem is that now we'll have a third 
>cluster node, and the failover mode will no more 
>be feasible.

Ok, I see a number of options.
You could continue with just two nodes running 
DHCP - losing one would be irritating, losing a 
second could be considered careless ;-)

Or, you could split the pools up and run a three 
way failover - whilst any pool may only be shared 
across two servers, you can share different pools 
with different servers. So setup three pools (a, 
b, and c), and have three servers (1, 2, and 3).

Pool a has failover between 1 & 2
Pool b has failover between 2 & 3
Pool c has failover between 1 & 3

So each server supports 2/3 of your address 
space, with failover to two separate servers.
If you lose any one server then "no-one notices"
If you lose two servers, then only 1/3 of the 
address space is affected, and clients will 
migrate to the other servers as their leases 
expire.

Of course, load is also plit 3 ways.

-- 
Simon Hobson

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