A little background first.....
I have inherited an exchange environment consisting of 2 Exchange 2010 Servers. We currently have 4 Databases that are all on one of the Exchange Servers. Both servers contain HUB, CAS and Mailbox roles. There is no DAG setup currently (this will be my next project).
I have setup a Hardware Load Balancer to begin my project for making this setup High availability.
My question is about setting up a CAS Array after the fact. I know that if I set this up my current clients won't be pointing to this. I will have to touch each client or push something out using GP. This isn't a big deal and I can deal with that. I want to make sure if I create the CAS Array and add the databases to it that the current users won't be left without access to mail until I am able to fix their outlook profile?
Thanks
Greg