Checkpoint Manager is the component of Cluster Service which monitors the changes in the Resources on a Cluster. This saves the Resource registry changes .cpt format on the Quorum drive. The details of the Resource’s registry details are written to the quorum drive, when the resource comes Online, so that that the Cluster can recover from a Resource failure.
When a resource is online, Checkpoint Manager monitors the changes to the Resources’ registry keys and writes it to the quorum drive in batches (not instantaneously).
The details of the resource can be located in the registry as,
The SQL Server key can be located where the “Type” equals “SQL Server”.
In this case, the key for SQL Server is bd12cba9-4da4-406e-b74e-6863671d304b
The .cpt file details are located in “RegSync” subkey
Here there are 7 .cpt files (see the names are from 00000001 to 00000007). The corresponding .cpt files are located at Q:\MSCS\bd12cba9-4da4-406e-b74e-6863671d304b.
Sometimes, the settings of a Resource on the Active node may not match with that of the passive node. With this knowledge, we can easily troubleshoot the issue by comparing the registry entries/cpt files by failing over the resources on to each node.