I have Unity pulling users mailboxes from our exchange server. We
intend upgrading this servers currently in a cluster (complete hardware
replacement)building a new cluster and changing the names of the servers.
What do I need to be concerned about in regards to Unity? How can I make sure Unity
works with our new Exchange Cluster? Is there a configuration section in unity I can go to to point The new cluster to Unity?
Your cluster should be fine. It's also assumed the current Exchange users alias's are not changing. If they are, then Unity will an issue. The alias is it's unique identifier. Basically if you were to take down your Exchange server, (AD is still the same, no changes) rebuild Exchange to a different name or version or cluster, you would need to do the following:
Rerun permissions wizard
rerun Mailstore configuration wizard.
Unity should resync backup with Exchange you should be set.
I would however probably leave your existing Exchange running, build your new cluster enviroment, then rerun permissions and mailstore wizard to add in the information stores and Exchange server, rather than taking it down completely, etc.