Reused Page Management for Log-Structured Flash Storage Systems

Recently, a flash memory has become a major database storage in building portable information devices because of its non-volatile, shock-resistant, power-economic nature, and fast access time for read operations. We propose a new scheme called flash memory shadow paging (FMSP) scheme for efficient page management in a flash memory database environment. We improved traditional shadow paging schemes by reusing old data pages which are supposed to be disposed in the course of writing a new data page in the flash memory file systems. In order to reuse these data pages, we devised a deferred cleaning mechanism and an operation interface which is geared to existing flash file systems. FMSP contributes to overcome the two drawbacks of traditional shadow paging schemes, additional space overhead and slow access caused by page distribution.