Prerequisite Considerations for Adding a DTC Resource to a Cluster
Applies To: Windows 10, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server Technical Preview, Windows Vista
Microsoft Windows XP and Microsoft Windows Server 2003 have certain requirements that you must be aware of prior to adding a DTC resource to a cluster. The following table lists these requirements and the corresponding factors to be considered.
Note
Only one DTC resource can be added to a cluster.
| Requirement | Determining factor |
|---|---|
| A DTC resource must be added to a cluster group. This group can be either an existing cluster group or a new group that you define. | If you want other cluster resources to failover with the DTC, those resources must reside in the same folder as the DTC resource. Note: For example, if you use the DTC with Microsoft SQL Server and you want them to failover together, you must add the DTC resource to the group in which SQL Server resides. |
| If you create a new group for the DTC resource, you must assign a name to that group. | Remember that no two groups in a cluster can have the same name. |
| A DTC resource has two resource dependencies—a physical disk and a network name. You must ensure that these DTC dependencies reside in the same group as the DTC resource. Note: An IP address resource is added automatically when you add a network name resource. | Because multiple physical disk resources are allowed in a group, you must decide where you want the DTC log file to reside. |
| The log file must reside on a disk that is shared by all nodes in the cluster. | When you install the DTC in a clustered environment, Windows XP and Windows Server 2003automatically create the DTC log file in the %Windows%/System32/msdtc folder. The name of the log file is msdtclog. In some cases, other resources in the group can share the physical disk with the DTC. In other cases, however, you might want the DTC log file to have its own disk. For example, if SQL Server requires a significant amount of disk space, you could move the DTC log file to a physical disk that has ample space. You can move the log file after you have configured the DTC as a cluster resource. |
| One or more nodes in the cluster must be identified as owners of the DTC resource. | Which nodes in the cluster are to be owners of the DTC resource? |
The following sections describe the tasks that you must perform before adding a DTC resource to a cluster.
Creating a Cluster Group for a DTC Resource
If you want to add a DTC resource to a new cluster group, you can use the Cluster Administrator tool create a group. The decision on whether or not to create a new group for a DTC resource depends largely on what resources are available in the cluster to the DTC. For example, if the DTC does not need to share a disk from another group, the DTC resource and its dependent physical disk resource can reside in a separate group.
Note
The DTC ensures that applications are able to communicate with a DTC resource even if the DTC resource is running on a separate node.
Adding DTC Resource Dependencies
A resource dependency is a resource type that the DTC requires so that it can operate successfully in a cluster. A DTC resource has the following two resource dependencies:
A physical disk resource An example of a physical disk resource is C:.
A network name resource An example of a network name resource is Cluster1.
The cluster group to which you add the DTC resource might not always contain the correct resource dependencies. Usually, this is because you have created a new cluster group for the DTC resource, which is always empty until you add resources to it.
To add resource dependencies to a new cluster group, you must move them from another group in which they currently reside. You cannot copy resources from one group to another. If two cluster resources have the same resource dependency, both cluster resources must reside in the same cluster group.
For example, if a DTC resource and a Microsoft SQL Server resource both have the physical disk F: as a dependency, both the DTC and the SQL Server resources must reside in the same group. However, if only one of the resources has the dependency on F:—for example, the DTC—the dependency resource F: can be moved from the group in which SQL Server resides to the new group defined for the DTC.
Choosing the Location for the DTC Log File
In a clustered environment, Windows XP and Windows Server 2003 include a shared instance of the DTC. This shared instance includes a log file that is automatically installed in a default location—%/Windows%/System32/msdtc/msdtclog—that can be shared by all owners of the DTC resource.
For performance reasons, you might want to move the log file. For example, if you have a Microsoft SQL Server resource and that resource is the only resource that requires transactions, you might want the DTC log file to reside on the same physical disk as the SQL Server resource.
You can move the DTC log file after you have configured the DTC as a cluster resource.
Choosing Owners for a DTC Resource
Before adding a DTC resource to a cluster, you must decide which nodes in the cluster should be designated as owners of the resource. You designate a node as an owner of a DTC resource when you add the resource. Choosing owners for a DTC resource is done using the same procedure as for other cluster resources.
See Also
Changing DTC Resource Dependencies
Cluster Administrator and DTC Configurations
DTC Transaction Manager on a Windows Server Cluster
Failover and Failback in Windows XP and Windows Server 2003
Managing a DTC Resource When a Node Is Evicted
Managing DTC Resources in Windows XP and Windows Server 2003