Exchange 2010 includes a feature called Datacenter Activation Coordination (DAC) mode that is designed to prevent split brain at the database level during switchback procedures that are being performed after a datacenter switchover has occurred. One of the side benefits of enabling DAC mode is that it enables you to use the built-in recovery cmdlets to perform the datacenter switchover and switchback.
In the real world, there are several different factors that determine what commands to run and when to run them. For example:
- Are Exchange Servers available in the primary datacenter?
- Is network connectivity available between the primary and remote datacenter?
- Is Exchange deployed in a topology with a single Active Directory site or multiple sites?