In a
Clustered Continuous Replication (CCR) cluster, the replay happens immediately after validation. In a
Local Continuous Replication (LCR) cluster, it is batched on 10 logs or 60 seconds, whichever comes first.
This is changed in Service Pack 1, and LCR no longer batches replay. Because the passive node must wait
for the active log file to be closed, there is a delay in the passive node ??™ s ability to stay completely in sync.
Continuous replication is used in three different high - availability solutions in Exchange Server 2007 with
Service Pack 1. The next few sections explain the differences between the models, and will help an
administrator decide which models are appropriate to meet the organization ??™ s service level agreements.
Chapter 12: Working with Continuous Replication
329
Clustered Continuous Replication
Now that continuous replication has been explained, the first solution to consider is Clustered
Continuous Replication (CCR). CCR is a high - availability solution that is built on top of WSSC, similar to
SCC described earlier. Figure 12 - 1 shows all of the pieces that make up a CCR.
Figure 12-1
First, CCR is limited to two nodes, one active and one passive. The virtual ??? floating ??? Exchange instance
is called the Clustered Mailbox Server. As shown in the figure, each node has its own separate storage.
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