*** Improved by Wrobinson on 9/9/08 ***
Windows and Exchange Server clusters are intended to provide high-availability. This comes at the cost of additional networking and storage complexity. It also requires a different approach for administrative tasks, such as service packs and upgrades.
You can add direct attached storage (DAS) to the existing Exchange Server solution without a performance penalty, so long as it is designed to meet the input/output per second (IOPS) requirement for your environment. In fact, a DAS solution affords more flexibility in the future, as you start to look at upgrading to Exchange Server 2007 or the next version.
*** End Updae ***
For master slave (avtice passive) exchange server u need configre your exchange server as active and passive mode cluster. here is the link that will help u
u want anything other then let me know.