We are looking at upgrading a Unity 4.05 Failover pair to Unity 5 with minimal disruption.
If we failover to the secondary server and upgrade the primary server will this cause problems when we then try and failback to the primary to allow the upgrade of the secondary?
Ideally I would like to take one server offline at a time and upgrade. Is this possible?
You can read about the upgrade here: http://www.cisco.com/en/US/partner/docs/voice_ip_comm/unity/white/paper/50curollupgrade.html
I just did it in a test environment, the procedure is roughly like this:
1 failover to secondary
2 upgrade primary
3 force secondary inactive
4 force primary active
5 upgrade secondary
6 reinstall failover monitor on both servers
The failover thing doesn't work when one is still ver 4.5 and the other is 5.0 so that is the reason for the forcing in 3 & 4. It seemed to work reasonably well for me.