Simple definition
DFSR replicates SYSVOL between Active Directory domain controllers to distribute Group Policy files.
Purpose and use
DFSR, Distributed File System Replication, replicates SYSVOL Group Policy files and scripts between domain controllers using that mechanism.
How does it work?
File replication is separate from replication of objects and attributes stored in the Active Directory database.
Example and verification
For inconsistent policy results, inspect both the directory object and SYSVOL files available on the controllers being used.
Points to watch
Error-free AD replication does not prove that DFSR is current. Forcing SYSVOL recovery without assessing available copies can worsen an incident.
In short
Policy consistency depends on directory and file components and their respective replication mechanisms.