7.6 Decision Points for Deploying Exchange Clusters

When deciding whether to invest in a clustered Exchange Server environment, several issues must be considered and weighed in order to provide a return on investment (ROI) justification. Each organization will need to identify and analyze these issues introspectively. This section provides some decision points and questions an organization should consider before choosing to deploy Microsoft Exchange 2000 Server in a clustered environment. The intention is to give the reader valuable guidance that will aid in selecting clustered solutions based on qualitative thinking rather than technical or marketing hype. First, the leading causes of downtime must be considered. Most research shows that the leading causes of downtime can be ranked in the following order:

1. Infrastructure

2. Software failures

3. Operational/administrative

4. Hardware failures

Interestingly enough, most researchers agree that the least likely component to fail in your environment is hardware. This corroborates what hardware vendors hear from customers and from service return rates. The leading causes of downtime are more often related to events and activities outside of the server. Issues such as poorlytrained personnel, building outages (power or air conditioning), or flawed backup and restore procedures typically account for more downtime than events such as hard-drive failures. In addition, software failures caused by the interaction of the operating system with third-party tools or drivers are often the downtime culprits as well. Regardless of what research indicates, it is important for each organization to determine the leading causes of down time on an organizational basis. It...