Check volume-root FSRM quotas when File Sync tiering never settles

Source facts

Microsoft recommends folder-level rather than volume-level FSRM quotas for File Sync server endpoints. A hard quota at the volume root can make the quota-restricted capacity differ from actual free space. File Sync can consequently keep tiering because it perceives insufficient available space.

Cloud tiering is not supported on the Windows system volume. For supported deployments, Microsoft recommends monitoring recall volume and cache hit rate when adjusting tiering policies. Microsoft Learn.

Applicability

Identify the endpoint volume, hard-quota location, quota limit and reported free space. Distinguish a quota-space mismatch from an independently established need to reduce the local cache.

DSE recommendation

DSE recommends inspecting quota placement before repeatedly raising the free-space target or forcing more data out of cache. Coordinate any move to folder-scoped quotas with the storage owner so the intended capacity restriction remains enforced. Do not remove a quota solely to suppress symptoms without understanding what it protects. Keep the tiering policy review tied to actual access and recall observations.

Verification

In a representative approved test, compare physical and quota-restricted space before and after the selected quota correction. Observe whether tiering behavior settles and whether the intended quota still applies. Track recall and cache-hit evidence over the agreed observation period rather than accepting a single free-space reading. Preserve continued tiering or unexpected capacity exposure as an unresolved finding.

Official references

Microsoft Learn: Choose Azure File Sync Cloud Tiering Policies. Source retrieved September 9, 2026.