In my last posts I discussed Exchange Server 2007 Single Copy Clusters, which is one of two clustering features available in Exchange.  In this post I will discuss the other type of Exchange Server 2007 clustering, Cluster Continuous Replication

What is Cluster Continuous Replication?

Cluster Continuous Replication (CCR) for Exchange Server 2007 would not be familiar to anyone who only has clustering experience with previous versions of Exchange.  In a CCR cluster two cluster server nodes connect to non-shared resources in an active/passive configuration.  Exchange storage group and mailbox database information is replicated between the active and passive node using asynchronous log shipping.  I explained asynchronous log shipping in the first part of this series on the basic concepts of Exchange Server 2007 high availability.  The same log shipping occurs in Local Continuous Replication.

The two CCR cluster nodes appear to other computers to be a single system, and when one server node fails the clustered resources are able to fail over to the other node and continue operation.

CCR provides high availability for the Mailbox Server by protecting it from the failure of either cluster server node, as well as protecting it from storage failure.  Because each cluster node is connected to its own non-shared storage, the failure of one does not impact the other.  This also means that CCR disk storage can consist of much cheaper hardware alternatives than an enterprise-grade SAN would cost, making Exchange high availability a reality for businesses with smaller budgets. Continue reading Exchange Server 2007 High Availability Part 4 – Cluster Continuous Replication