VMware Compatibility Guide

vSphere Storage APIs for Storage Awareness, commonly referred to as VASA, is a set of APIs that permits storage arrays to integrate with vCenter for management functionality. VASA can display the features of the physical storage devices, allowing vSphere administrators insight into storage capabilities. Our storage array partners are creating plugins called vendor providers, which is the integration "glue" that sits between vCenter and the storage array. Vendor providers retrieve the storage capabilities from the array and pass these onto vCenter, which in turn can display these capabilities in the UI. VASA may also provide information about storage health status, configuration info & capacity. For the first time VMware has an end to end story, i.e. storage array informs the vendor provider of capabilities & then the vendor provider informs vCenter. Admins can now see storage array capabilities from the vSphere client, giving them a single window into both the virtualization & storage infrastructures.
In this first release of the VASA framework, vendor providers will surface a single "attribute" per LUN from the storage array to vCenter server. This attribute can take many forms as we are leaving this format decision to the storage vendors. One of the cool features of VASA is that it lends itself to the creation of VM Storage Profiles (aka Profile Driven Storage), another new feature of vSphere 5.0. In addition to capability discovery, VASA also offers capacity and health monitoring. Storage DRS, another new vSphere 5.0 feature, includes recommendations from VASA providers in its load balancing logic and also monitors for Thin Provisioning alarm status which avoids moving VMs to datastores that are in danger of running out of space on the backing storage.

Please refer to the Hardware Compatibility List for all partner related VASA providers.