Just configure your clients for both data zones but disable the groups/workflows to run automatic backups.
Then whenever you need it, simply set autostart=enabled and watch the backups.
One thing to consider is that the media index will not have a backup of the 'new' clients.
Therefore they will all run fulls at the first time.
Do not forget to
- extend the /nsr/res/servers file on all clients to match both servers and
- to restart their nsrexec daemon/service.
From my description. there will be Networker at both site. Normally one will stand as hot standby in case the prod is unreachable. In this case, data is generated at both site. As a result, Networker at the DR will not only be the hot standby but also do the primary job of backing up clients to Data Domain.
I don't see why is it so important to have a standby server which can do only backups for you.
We have also a 2 site setup (active-active), NetWorker is running only on 1 site and it is protected by: vmware SRM + it's own bootstrap backup. We have 2 datadomains, each client sends the backup to its local datadomain but we also replicate all backups between sites.
In case of site failure (where the NW server is) we can start up the server on the other site and we can continue the operation.
However if you have 2 distinct NW servers you can have all client definitions / backup policies etc., but you cannot access any backup data created by the other server(*). You can't replicate backups to an another NW server, you can do it only if you configure backup media on both DataDomains on the same server.
(*): you can read-in any networker backups from a device using the scanner tool, but it takes really huge amount of time
A good way to achieve this is to have NetWorker server in cluster Node C (Node A and Node B at different sites forming cluster) which will have /nsr directory shared between them. DD A & DD B will accept data from respective site clients from local site.
Benefit of running this in cluster is you will be able to recover old data Backed-up for client from any site at any point of time without taking hard efforts of scanning/mounting DD volumes through different server.
This is the best and easy way to do it.
Let me know if you want to hear the complex one as well.