Storage DRS generates an alarm to indicate that it cannot operate on the datastore.
Storage DRS generates an event and an alarm and Storage DRS cannot operate.
The following scenarios can cause vCenter Server to disable Storage DRS for a datastore.
The datastore is shared across multiple data centers.
Storage DRS is not supported on datastores that are shared across multiple data centers. This configuration can occur when a host in one data center mounts a datastore in another data center, or when a host using the datastore is moved to a different data center. When a datastore is shared across multiple data centers, Storage DRS I/O load balancing is disabled for the entire datastore cluster. However, Storage DRS space balancing remains active for all datastores in the datastore cluster that are not shared across data centers.
The datastore is connected to an unsupported host.
Storage DRS is not supported on ESX/ESXi 4.1 and earlier hosts.
The datastore is connected to a host that is not running Storage I/O Control.
The datastore must be visible in only one data center. Move the hosts to the same data center or unmount the datastore from hosts that reside in other data centers.
Ensure that all hosts associated with the datastore cluster are ESXi 5.0 or later.
Ensure that all hosts associated with the datastore cluster have Storage I/O Control enabled.