When I/O filters are installed on ESXi hosts, the I/O filter framework configures and registers a storage provider, also called a VASA provider, for each host in the cluster.
Storage providers for I/O filtering are software components that are offered by vSphere. They integrate with I/O filters and report data service capabilities that I/O filters support to vCenter Server.
The capabilities populate the VM Storage Policies interface and can be referenced in a VM storage policy. You then apply this policy to virtual disks, so that the I/O filters can process I/O for the disks.