Wayback: a user-level versioning file system for linux
Brian Cornell, Peter A. Dinda, Fabián E. Bustamante · 2004
In a typical file system, only the current version of a file (or directory) is available. In Wayback, a user can also ac-cess any previous version, all the way back to the file’s creation time. Versioning is done automatically at the write level: each write to the file creates a new version. Wayback implements versioning using an undo log structure, ex-ploiting the massive space available on modern disks to provide its very useful functionality. Wayback is a user-level file system built on the FUSE framework that relies on an underlying file system for access to the disk. In ad-dition to simplifying Wayback, this also allows it to extend any existing file system with versioning: after being mounted, the file system can be mounted a second time with versioning. We describe the implementation of Way-back, and evaluate its performance using several benchmarks. 1