Hello,
First, be aware that the MSA array does not support VMware's VVols. Don't confuse vvols with virtual volumes on the MSA array as they are two separate concepts.
vSphere APIs for Storage Awareness (VASA) is an API mechanism that allows communication between vCenter, the storage array, and the ESXi hosts. The VASA for non-vvol will be the APIs that allow the ESXi hosts and vCenter to communicate with the storage (aka MSA array).
The APIs for non-vvol communication will be different than the APIs used for vvols. Remember that vvols provisions storage differently than the way external storage does with LUNs attached to a SAN.
Cheers,
Shawn
I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.