Creating a highly available mailbox server infrastructure

In contrast to creating high availability for your Client Access Server infrastructure, doing it for your mailbox servers is quite different. Since Exchange's early days, you had to create a cluster (with shared storage) if you wanted Exchange to be somewhat highly available. At that time, the clustering components upon which Exchange relied were notorious for their difficulty to set up, maintain, and troubleshoot.

Over time, Microsoft made significant changes to the failover clustering component in Windows, improving the overall experience. Not only for the administrator, but also from an end user's perspective. Even today with Windows Server 2012, Microsoft keeps on improving dramatically.

Creating a cluster might ensure you servers are highly available, they usually don't care what the state of the data is. In the past, Exchange clusters relied heavily on the underlying storage to provide high availability. At the same time, it was...