Volume Reference Counts Help Detect Orphaned Docker State

Old Docker volumes can consume storage after services are removed, and their names alone do not always reveal whether anything still depends on them. The monitoring mistake would be to read one metric in isolation. Docker volume size plus reference-count inventory is useful because it narrows the question, and reference counts distinguish active persistent state from likely orphaned volumes and make cleanup review safer.

In software operations this falls under inventory-assisted storage monitoring. A dashboard becomes much more valuable when the operator knows what a rising line can prove, what it cannot prove, and which second signal should confirm the hypothesis.

My prevention rule is: Show size and attachment count together, then verify ownership and backup status before deleting any unreferenced volume. That keeps false positives lower without weakening visibility into real degradation.

The hserver source evidence is 218300b. Keeping that provenance matters because monitoring logic changes over time; the article should remain connected to the exact engineering decision it describes.