windows_exporter/internal/collector/dfsr/AGENTS.md

dfsr collector

The collector reads three PDH objects with pdh.CounterTypeRaw: DFS Replication Connections, DFS Replicated Folders and DFS Replication Service Volumes. They exist only where the DFS Replication service runs, for example on every domain controller (SYSVOL). CI does not provision DFSR. These notes were recorded on a single Windows Server 2025 DC.

• Every counter of the three objects is PERF_COUNTER_LARGE_RAWCOUNT (NumberOfItems64). The type does not say whether the value is cumulative, so go by the counter help text:
  • Cumulative since service start: the ... Generated, ... Cleaned up, ... Received, File Installs ..., Updates Dropped, Database Commits, Database Lookups and USN Journal Records Read/Accepted counters.
  • Gauges: Staging/Conflict/Deleted Space In Use (bytes), USN Journal Unread Percentage, connection Bytes Received Per Second, and Bandwidth Savings Using DFS Replication, which is a percentage ("a value of 20 indicates ... 20% less bandwidth"), not bytes. The collector publishes it and USN Journal Unread Percentage (0-100) as _ratio gauges divided by 100.
• The collect*Metrics functions take rows, so tests can check names, types and values through a registry without a live DFSR service (dfsr_internal_test.go).
• Instances: folders are <replicated folder>-{<GUID>}, for example SYSVOL Share-{DD658FCA-D7AE-487D-8E75-67481CEBE108}; volumes are drive letters (C:). A DC without replication partner has no instance of DFS Replication Connections, so connection metrics are not exercised there.
• Sample from the DC (volume C:): USN Journal Records Read 1932712, Database Commits 800998, Database Lookups 1058283, USN Journal Records Accepted 0, USN Journal Unread Percentage 0. All folder counters of SYSVOL were 0.

Counter reference

Recorded on Windows Server 2025 (build 26100). Raw and Base are the first and second values that pdh.CounterTypeRaw returns for the sample instance.

DFS Replicated Folders

Multi-instance. Instances: SYSVOL Share-{DD658FCA-D7AE-487D-8E75-67481CEBE108}. Sample instance: SYSVOL Share-{DD658FCA-D7AE-487D-8E75-67481CEBE108}.

Counters the collector reads:

Counter	Type	Raw	Base
Bandwidth Savings Using DFS Replication	PERF_COUNTER_LARGE_RAWCOUNT	0
Compressed Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT	0
Conflict Bytes Cleaned up	PERF_COUNTER_LARGE_RAWCOUNT	0
Conflict Bytes Generated	PERF_COUNTER_LARGE_RAWCOUNT	0
Conflict Files Cleaned up	PERF_COUNTER_LARGE_RAWCOUNT	0
Conflict Files Generated	PERF_COUNTER_LARGE_RAWCOUNT	0
Conflict Folder Cleanups Completed	PERF_COUNTER_LARGE_RAWCOUNT	0
Conflict Space In Use	PERF_COUNTER_LARGE_RAWCOUNT	0
Deleted Bytes Cleaned up	PERF_COUNTER_LARGE_RAWCOUNT	0
Deleted Bytes Generated	PERF_COUNTER_LARGE_RAWCOUNT	0
Deleted Files Cleaned up	PERF_COUNTER_LARGE_RAWCOUNT	0
Deleted Files Generated	PERF_COUNTER_LARGE_RAWCOUNT	0
Deleted Space In Use	PERF_COUNTER_LARGE_RAWCOUNT	0
File Installs Retried	PERF_COUNTER_LARGE_RAWCOUNT	0
File Installs Succeeded	PERF_COUNTER_LARGE_RAWCOUNT	0
RDC Bytes Received	PERF_COUNTER_LARGE_RAWCOUNT	0
RDC Compressed Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT	0
RDC Number of Files Received	PERF_COUNTER_LARGE_RAWCOUNT	0
RDC Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT	0
Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT	0
Staging Bytes Cleaned up	PERF_COUNTER_LARGE_RAWCOUNT	0
Staging Bytes Generated	PERF_COUNTER_LARGE_RAWCOUNT	0
Staging Files Cleaned up	PERF_COUNTER_LARGE_RAWCOUNT	0
Staging Files Generated	PERF_COUNTER_LARGE_RAWCOUNT	0
Staging Space In Use	PERF_COUNTER_LARGE_RAWCOUNT	0
Total Files Received	PERF_COUNTER_LARGE_RAWCOUNT	0
Updates Dropped	PERF_COUNTER_LARGE_RAWCOUNT	0

DFS Replication Connections

Multi-instance. No instances on the recording host, so the table has types only.

Counters the collector reads:

Counter	Type	Raw	Base
Bandwidth Savings Using DFS Replication	PERF_COUNTER_LARGE_RAWCOUNT
Compressed Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT
RDC Bytes Received	PERF_COUNTER_LARGE_RAWCOUNT
RDC Compressed Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT
RDC Number of Files Received	PERF_COUNTER_LARGE_RAWCOUNT
RDC Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT
Size of Files Received	PERF_COUNTER_LARGE_RAWCOUNT
Total Bytes Received	PERF_COUNTER_LARGE_RAWCOUNT
Total Files Received	PERF_COUNTER_LARGE_RAWCOUNT

Not read by the collector:

• PERF_COUNTER_LARGE_RAWCOUNT: Bytes Received Per Second

DFS Replication Service Volumes

Multi-instance. Instances: C:. Sample instance: C:.

Counters the collector reads:

Counter	Type	Raw	Base
Database Commits	PERF_COUNTER_LARGE_RAWCOUNT	802516
Database Lookups	PERF_COUNTER_LARGE_RAWCOUNT	1060537
USN Journal Records Accepted	PERF_COUNTER_LARGE_RAWCOUNT	0
USN Journal Records Read	PERF_COUNTER_LARGE_RAWCOUNT	1936015
USN Journal Unread Percentage	PERF_COUNTER_LARGE_RAWCOUNT	0