File Versioning for Block-Level Continuous Data Protection

Block-level continuous data protection (CDP) logs every disk block update so that disk updates within a time window are undoable. Standard file servers and DBMS servers can enjoy the data protection service offered by block-level CDP without any modification. Unfortunately, no existing blocklevel CDP systems can provide users a file versioning view on top of the block versions they maintain. As a result, the data they maintain cannot be used as an an extension to the on-line system with which users routinely interact. This paper describes a name-based user-level file versioning system called UVFS that is designed to reconstruct file versions from disk block versions maintained by a blocklevel CDP. UVFS reconstructs file versions by following the last modified time of files and directories, a common file metadata supported by almost all modern file systems, and therefore does not require any modification to the host file system that a block-level CDP system protects. In add...

• Type: Conference
• Year: 2009
• Where: ICDCS
• Authors: Maohua Lu, Tzi-cker Chiueh
• Keywords: Block-level Cdp System, Block-level Continuous Data, Computer Science, ICDCS 2009, Pointin-time Block-level Snapshot