Clustered SQL Server 2005: is MSDTC required?

If you have a clustered SQL Server instance, with SSIS or Notification Services or Workstation components the definitive answer is YES, you need to install MSDTC.

And it has to be clustered.

Source: https://msdn2.microsoft.com/en-us/library/ms189910.aspx

"Before installing SQL Server 2005 on a failover cluster, determine whether the Microsoft Distributed Transaction Coordinator (MSDTC) cluster resource must be created. If you are installing only the Database Engine, the MSDTC cluster resource is not required. If you are installing the Database Engine and SSIS, Notification Services, or Workstation Components, you must install MSDTC. This requirement applies to both Windows 2000 and Windows Server 2003 operating systems".

Source: https://support.microsoft.com/kb/294209/:

"Microsoft only supports running MSDTC on cluster nodes as a clustered resource. We do not recommend or support running MSDTC in stand-alone mode on a cluster. Using MSDTC as a non-clustered resource on a Windows cluster is problematic. This configuration is problematic because transactions could be orphaned and you may experience data corruption if a cluster failover occurs."

If you don't, you will still be able to install SQL Server 2005 (with a warning) but you won't be able to upgrade to SQL 2005 SP2.

- Beatrice Nicolini -