Hi All, 

We have 2K8 R2 DCHP server running as a Central DHCP server located in Central site.This server caters almost 60-65 scopes for various sites and for redundancy purpose we have one more 2K8 R2 server, but currently the DHCP services are disabled and only will be active in case of disaster. We copy the DHCP files as a backup from primary server to secondary server

Now we are planning to upgrade the central DHCP server 2k12 R2, with below VM configuration 100 GB C: drive, 8 GB of RAM 

setup would be similar like 2K8 R2, My questions is

1. Can we retain the Same IP address for both the server, as they have been configured on 55-60 sites as IP helper

2. Whether we should restore the backup on new server with all the current Scope and reservations

3. To work as a Cluster (may not be right term), if primary goes down, secondary will be up (Not automated, but by few clicks)

Let me know if you need any more information.

Thanks

Hi,

1. Yes you can keep the IP but you need a temporary IP for the 2012 until you move/restore/migrate the scopes and other settings to the new server, then you can swap IPs and keep the authorized one asuming this is in an AD domain.

2. I have seen people using scripts to copy scopes and reservations, others dping import/export.

3. You can use this link to configure replication between 2 2012 R2 servers and see some migration aproaches:

http://blogs.technet.com/b/teamdhcp/archive/2012/09/11/migrating-existing-dhcp-server-deployment-to-windows-server-2012-dhcp-failover.aspx

Hope it helps.

Regards,

Calin

Thanks Calin, 

Can you please suggest on VM Specs, both the VM's will have only DHCP role

Hi,

Well, I would start with 4GB, 60-70 GB disk size (so you have room for patching) and 1vCPU. You may increase RAM in case you see performance issues. The database will eat very few disk space even with hundreds of scopes and settings.

Hope this helps.

Regards,

Calin