Towards Efficient, Portable Application-Level Consistency

Applications employ complex protocols to ensure consistency after system crashes. Such protocols are affected by the exact behavior of file systems. However, modern file systems vary widely in such behavior, reducing the correctness and performance of applications. In this paper, we study application-level crash consistency. Through the detailed study of two popular database libraries (SQLite, LevelDB), we show that application performance and correctness heavily depend on file-system properties previously ignored in research. We define a number of such properties and show that they vary widely among file systems. We conclude with implications for future file-system and dependability research.