FlexVol: Flexible, Efficient File Volume Virtualization in WAFL

Virtualization is a well-known method of abstracting physical resources and of separating the manipulation and use of logical resources from their underlying implementation. One has used this technique to virtualize file volumes in the WAFL R file system, adding a level of indirection between client-visible volumes and the underlying physical storage. The resulting virtual file volumes, or FlexVol R volumes, are managed independent of lower storage layers. Multiple volumes can be dynamically created, deleted, resized, and reconfigured within the same physical storage container.