If you have worked with the previous versions of Exchange, you may have been involved in implementing or supporting a high-availability solution that required a shared storage model. This allowed multiple server nodes to access the same physical storage, and, in the event of an active server node failure, another node in the cluster could take control of the cluster resources since it had local access to the databases and logfiles. This was a good model for server availability, but did not provide any protection for data redundancy.
With the release of Exchange 2007, Microsoft still supported this shared-storage clustering model, re-branded as Single Copy Clusters (SCC), but they also introduced a new feature known as continuous replication. Among the three types of continuous replication options provided, Cluster Continuous Replication (CCR) was the high-availability solution for Exchange 2007 that eliminated the potential risk of a single point of failure at the storage level...