Reliability Enhancement of Flash-Memory Storage Systems: An Efficient Version-Based Design

In recent years, reliability has become one critical issue in the designs of flash-memory file/storage systems, due to the growing unreliability of advanced flash-memory chips. In this paper, a version-based design is proposed to effectively and efficiently maintain the consistency among page versions of a file for potential recovery needs. In particular, a two-version one for a native file system is presented with the minimal overheads in version maintenance. A recovery scheme is then presented to restore a corrupted file back to the latest consistent version. The design is later extended to maintain multiple data versions with the considerations of the write constraints of multilevel-cell flash memory. It was shown that the proposed design could significantly improve the reliability of flash memory with limited management and space overheads.