Registry replication in Microsoft Cluster Server

MSCS provides the ability for Generic Service and Generic Application resource types to specify registry keys below HKEY_LOCAL_MACHINE that should be replicated to all nodes in the cluster.


Some services or applications may update registry information while they are running by use of Win32 registry functions. MSCS provides registry checkpointing for noncluster aware applications that may use these functions. Registry checkpointing for these resources occurs under the following conditions:

• When you specify a new registry key for the resource, the specified key is checkpointed.
  
• When the resource goes online, the registry keys are updated with the previously checkpointed information.
  
• When the resource is brought offline, all the checkpoints associcated with this resource are saved.
  
• When the resource is online and changes are made to the registry key which is registered with the cluster server for replication, MSCS ensures that the updates are written to a checkpoint maintained on the quorum device.
  

If you manually update these registry keys while the application or service is offline, the changes may not be replicated or may be lost. To prevent this from happening, make any manual changes while the service or application resource is online.


Cluster aware applications should make use of cluster registry functions as provided in the cluster API set when working with registry keys under HKEY_LOCAL_MACHINE\Cluster. Consult the MSCS Software Development Kit (SDK) for more information on this topic.