Here's an interesting architecture around the emerging trends around storage and specifically around scale-out NAS solutions. This article does a good job explaining the needs for scale-out NAS solutions and their evolution into cloud based solutions.
The article mentions some potential solutions that include Symantec's FileStore product. FileStore is one of the fastest performing scale-out NAS solutions in the market. While VirtualStore is not mentioned in this article it is a completely software solution that can be used to gain the same benefits mentioned in the article while using existing storage hardware.