In this paper, we introduce the No-Order File System (NoFS), a simple, lightweight file system that employs a novel technique called backpointer based consistency to provide crash consistency without ordering writes as they go to disk. A backpointer is added to each object in the file system, and the forward and backward pointers allows us to determine consistency by cross-checking the pointers. This simple inclusion surprisingly allows us to guarantee consistency in a wide range of crash scenarios.
We utilize a formal model to prove that NoFS provides data consistency in the event of system crashes; we show through experiments that NoFS is robust to such crashes, and delivers excellent performance across a range of workloads. Backpointer based consistency thus allows NoFS to provide crash consistency without resorting to the heavyweight machinery of traditional approaches.