Write Anywhere File Layout (WAFL)

The WAFL (Write Anywhere File Layout) file system contributes to a high level of data availability while providing dynamic and flexible data storage containers using Flexible Volume technology as well as data protection using integrated, nonvolatile RAM and a block-level checksum capability. The WAFL file system is designed specifically to work in an NFS appliance. The primary focus is on the algorithms and data structures that WAFL uses to implement Snapshots, which are read-only clones of the active file system. WAFL uses a copy-on-write technique to minimize the disk space that Snapshots consume.