Association for Computing Machinery
Synchronous transactional logging is the central mechanism for ensuring data persistency and recoverability in database systems. Unfortunately, magnetic disks are ill-suited for the small sequential write pattern of synchronous logging. Alternative solutions (e.g., backup servers or sophisticated battery-backed write caches in high-end disk arrays) are either expensive or complicated. In this paper, the authors exploit flash devices for synchronous logging based on the observation that flash devices support small sequential writes well. Comparing a wide variety of flash devices, they find that USB flash drives are a good match for this task because of its unique characteristics: widely available USB ports, hot-plug capability useful for coping with flash wear, and low price so that multiple drives are affordable.