FlexVol: Flexible, Efficient File Volume Virtualization in WAFL

zation is a well-known method of abstracting physical resources and of separating the manipulation and use of logical resources from their underlying implementation. We have 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. We also exploit this new virtualization layer to provide several powerful new capabilities. We have enhanced SnapMirror R , a tool for replicating volumes between storage systems, to remap storage allocation during transfer, thus optimizing disk layout for the destination storage system. FlexClone R volumes provide writable Snapshot R copies, using a FlexVol volume backed by a Snapshot copy of a different volume. FlexV...

• Type: Conference
• Year: 2008
• Where: USENIX
• Authors: John K. Edwards, Daniel Ellard, Craig Everhart, Robert Fair, Eric Hamilton, Andy Kahn, Arkady Kanevsky, James Lentini, Ashish Prakash, Keith A. Smith, Edward R. Zayas
• Keywords: File Volumes, Flexvol Volumes, Operating System, Physical Storage, USENIX 2008