(PhD15) HasFS: A File System for NVM-based Hybrid Storage Architecture
TimeMonday, June 25th1:57pm - 2:01pm
DescriptionIn traditional DRAM-based file systems (such as EXT4), file systems need to periodically synchronize the dirty data on the DRAM to the disk to protect against data crash because DRAM is a volatile media. Furthermore, some unpredictable system failures may break file system consistency. Therefore, many file systems use journaling to guarantee the file system consistency. In our observations, periodic disk synchronization and after-crash consistency guarantee (journaling) will significantly degrade file system performance at many workloads. So, we leverage NVM to tackle these two performance bottlenecks.
Currently, non-volatile main memory (NVM) brings some new motivations to file system optimization. We leverage NVM to tackle these two performance bottlenecks. We present HasFS, a file system designed for the DRAM-NVM-DISK architecture (Hybrid Architecture for Storage). HasFS extends the main memory with NVM and treats NVM as a persistent page cache to eliminate the periodic disk synchronization overhead of dirty data. In addition, traditional journaling is inefficient on HasFS architecture because it depends on the write ordering. Therefore, we designed an NVM-friendly, non-ordering consistency mechanism based on the hybrid storage architecture. This mechanism can provide strong consistency guarantee with low overhead. Our empirical evaluation demonstrates that HasFS outperforms DRAM-based file systems at many workloads, even through NVM is slower than DRAM.