Overview of a Fault Tolerant Messaging Infrastructure

To make your Exchange 2003 organization as fault tolerant as possible, you should minimize the single points of failure in your messaging infrastructure. You can do this by implementing fault tolerant measures at the following levels:

• **Operating system and application measures   **Before implementing specific component-level and system-level fault tolerant measures, there are certain operating system and application measures to consider.

• Component-level measures   At the server level, you should use fault tolerant components such as power control, battery backup, Error Correction Code (ECC) memory, and redundant fans. At the network-level, you should implement fault tolerant networking components such as redundant switches, routing, and wiring.

• System-level measures   At the system level, you should deploy Exchange using fault tolerant measures such as redundant access to Active Directory® directory service, redundant client access to front-end services, redundant storage of Exchange data, a carefully planned backup strategy, and a carefully planned monitoring strategy.

  Note

  It is not always necessary to implement redundant components in every level of your design. Specifically, you should consider the mean time between failures (MTBF) of each device in the critical path. In some cases, you may be able to reach your required availability levels even if there is no redundancy for some devices.

The following figure illustrates many of the system-level measures you can implement to maximize the fault tolerance of your Exchange organization.

Fault tolerant Exchange 2003 messaging infrastructure