(
Write
Anywhere
File
Layout) A high-performance journaling file system used in Network Appliance's NAS and caching devices. It natively supports RAID implementations and allows for expansion on the fly. Using a clever system of pointers to disk clusters that take up a small amount of extra disk space, WAFL enables up to 31 snapshots of the disk to be scheduled in order to roll back to previous versions of the data. See
Network Appliance.