Snapshot-Based Data Recovery Approach

In this paper, we present the design and implementation details of WOWSnap, which is the data backup scheme based on the snapshot approach. As data to be stored in storage subsystems are tremendously increased, data protection techniques have become more important, to provide data availability and reliability. Snapshot is one of such data protection techniques and has been adapted to many file systems. However, in large-scale storage systems, adopting a snapshot technique to prevent data loss from intentional/accidental intrusion is not an easy task because the data size being backup-ed at a given time may be huge. In this paper, we present the WOWSnap that has been implemented based on file system-based snapshot approach. The WOWSnap provides a widely portable structure and causes less I/O processing overhead than ROW (Redirect On Write) method. Furthermore, the WOWSnap provides a capability of maintaining the disk space assigned to snapshot images in a consistently-sized disk portion. We present the performance results of the WOWSnap obtained from the Linux cluster located at Sejong University. Key-Words: file system-based snapshot, data recovery, WOWSnap, snapshot pointer, spatial algorithm