What is the default I/O latency threshold for vSphere Storage DRS?

10ms is too aggressive and is not the default; it would trigger migrations under normal, healthy I/O conditions.

30ms is well above the default and would allow datastores to sustain high latency before Storage DRS reacts.

15ms is the factory-default I/O latency threshold for Storage DRS. When the average device latency on a datastore exceeds this value, Storage DRS evaluates the cluster and generates recommendations or automatically migrates VMDKs to less-loaded datastores. This value balances sensitivity with stability, avoiding excessive churn while still reacting to meaningful congestion.

20ms is not the configured default threshold in vSphere Storage DRS, even though it may seem reasonable.