VVOLs, which is short for Virtual Volumes, enables an administrator to apply a policy to a VM which defines the various performance and service-level agreement requirements, such as RAID level, replication or deduplication. The VM is then automatically placed on the storage array that fits those requirements.
VVOLs' other advantage is the ability to snapshot a single VM instead of just the traditional snapshot of an entire logical unit number that may house several VMs. This feature saves wasted space on the data store and reduces the amount of administrative overhead.
To use VVOLs, the storage hardware has to support the vStorage APIs for Storage Awareness (VASA). VMware introduced VVOLS at VMworld 2011 during a technical preview session.