This article was previously published under Q174070
Microsoft Cluster Server (MSCS) provides the ability to replicatedesignated registry keys as associated with a Generic Service or GenericApplication resource types.
MSCS provides the ability for Generic Service and Generic Applicationresource types to specify registry keys below HKEY_LOCAL_MACHINE thatshould be replicated to all nodes in the cluster.
Some services or applications may update registry information while theyare running by use of Win32 registry functions. MSCS provides registrycheckpointing for noncluster aware applications that may use thesefunctions. Registry checkpointing for these resources occurs under thefollowing 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 serviceis offline, the changes may not be replicated or may be lost. To preventthis from happening, make any manual changes while the service orapplication resource is online.
Cluster aware applications should make use of cluster registry functions asprovided in the cluster API set when working with registry keys underHKEY_LOCAL_MACHINE\Cluster. Consult the MSCS Software Development Kit (SDK)for more information on this topic.