An administrator observes that virtual machine storage activity on an ESXi 6.x host is negatively affecting virtual machine storage activity on another host that is accessing the same VMFS…

Dynamic Queue Depth Throttling adjusts queue depth per path when congestion is detected but does not enforce fairness or I/O prioritization across different hosts sharing the same datastore.

Storage DRS balances VM placement and load across multiple datastores but does not control or throttle I/O between VMs competing on a single shared datastore.

Storage I/O Control monitors VMFS datastore latency and uses configurable I/O shares to fairly distribute storage bandwidth among all VMs accessing the same datastore across multiple ESXi hosts. When latency exceeds a threshold, SIOC throttles I/O from lower-priority VMs, ensuring no single host can starve others of storage resources. This directly addresses the cross-host storage contention described in the scenario.

The Disk.SchedNumReqOutstanding parameter limits outstanding I/O requests to a datastore per host locally, but does not coordinate I/O prioritization across multiple hosts sharing the same datastore.