Specifications

Best Practices for Virtualizing and Managing Exchange 2013
40
40
Figure 25: Cluster-Aware Updating Wizard
CAU can perform the cluster updating process in two different modes: self-updating mode and remote-
updating mode. In self-updating mode, the CAU clustered role is configured as a workload on the failover
cluster that is to be updated. In remote-updating mode, a remote computer running Windows Server
2012 or Windows 8 is configured with the CAU clustered role. This remote computer is also called the
Update Coordinator and is not part of the cluster that is updating.
Note that for many clustered roles in a cluster, the automatic updating process triggers a planned failover,
which, in turn, can cause a service interruption for a very short time (transient).
28
Best Practices and Recommendations
Use the CAU feature with continuously available cluster workloads in Windows Server 2012 to
perform updates on clusters with no impact on service availability. Examples of continuously
available cluster workloads in Windows Server 2012 are file servers (file server with SMB
Transparent Failover) and Hyper-V virtual machines with live migration. With CAU, virtualized
Exchange Servers experience no downtime, even though underlying hosts are being patched and
potentially taken offline for maintenance.
Create Updating Run Profiles for different classes of failover clusters, and store and manage them
on a centralized file share. This ensures that the CAU deployments consistently apply updates to
the clusters throughout the IT organization (even across different departments, line-of-business
areas, or administrators).