Migrating to Failover

Simon Hobson dhcp1 at thehobsons.co.uk
Tue Sep 15 14:13:34 UTC 2009

Norman Elton wrote:

>I've got a single DHCP server serving roughly a dozen subnets. I want
>to move this to a new pair of DHCP servers running failover. I'd like
>to do this in a controlled manner, one subnet at a time. It's easy to
>change the helper-address on a particular subnet, but I somehow need
>to migrate the leases to the new pair.

Can you clarify - are you migrating from a single server to a 
failover pair which does NOT include that single server, or adding 
another server to form a pair with the existing server ?

Unless someone knows otherwise, if you add a partner to an existing 
server then it will automatically synchronise it's leases. In that 
situation, I believe all you need to do is :
- add failover declaration to subnet on existing server
- add subnet declaration to new server
- restart existing server
- restart new server

If you are migrating to a completely new and different DHCP setup, 
then yes - you should copy (append) the lease database to the new 
servers. You need to be sure that there are no entries for addresses 
already in the new servers lease database - they would cause 
"unexpected" results.

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
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