The Composite-File File System
Shuanglong Zhang, Robert Roy, Leah E. Rumancik, An-I Andy Wang · ACM Transactions on Storage · 2020
The design and implementation of traditional file systems typically use the one-to-one mapping of logical files to their physical metadata representations. File system optimizations generally follow this rigid mapping and miss opportunities for an entire class of optimizations. We designed, implemented, and evaluated a composite-file file system, which allows many-to-one mappings of files to metadata. Through exploring different mapping strategies, our empirical evaluation shows up to a 27% performance improvement under web server and software development workloads, for both disks and SSDs. This result demonstrates that our approach of relaxing file-to-metadata mapping is promising.