What's the correct way to configure the Microsoft Distributed Transaction Coordinator (MSDTC) resource in a cluster? Should I put this resource in its own cluster group?
The official answer to your question is a little confusing. The Microsoft article "How to configure Microsoft Distributed Transaction Coordinator on a Windows Server 2003 cluster" (http://support.microsoft.com/?kbid=301600) recommends putting the MSDTC resource in its own resource group. But the "Exchange Server 2003 Cluster Configuration Checklist"(http://www.microsoft.com/technet/itsolutions/msit/operations/exchclustercklist.mspx), which is a white paper that describes how Microsoft has set up its own clusters, recommends putting the MSDTC resource in the same resource group as the quorum resources.
The reasons for the discrepancy are somewhat esoteric but revolve around the fact that the Exchange server doesn't actually use the MSDTC resource after Exchange setup is finished. Putting the resource in its own group ensures that a failure won't affect other applications. But because the MSDTC resource is rarely used, putting it into the quorum resource group, where it can share a disk with other resources, is fairly safe. If you choose the latter option, set the resource's state to offline and clear the Affect the group check box in the resource's Properties dialog box. These steps ensure that if the MSDTC resource does fail, it won't affect other resources on the server. Of course, if you've set up a cluster that runs both Exchange and Microsoft SQL Server, your SQL resources might require MSDTC; follow the SQL Server product team's recommendations for the location and configuration of the resource.