SpanFS: A Scalable File System on Fast Storage Devices

Most recent storage devices, such as NAND flash-based solid state drives (SSDs), provide low access latency and high degree of parallelism. However, conventional file systems, which are designed for slow hard disk drives, often encounter severe scalability bottlenecks in exploit-ing the advances of these fast storage devices on many-core architectures. To scale file systems to many cores, we propose SpanFS, a novel file system which consists of a collection of micro file system services called do-mains. SpanFS distributes files and directories among the domains, provides a global file system view on top of the domains and maintains consistency in case of system crashes. SpanFS is implemented based on the Ext4 file sys-tem. Experimental results evaluating SpanFS against Ext4 on a modern PCI-E SSD show that SpanFS scales much better than Ext4 on a 32-core machine. In micro-benchmarks SpanFS outperforms Ext4 by up to 1226%. In application-level benchmarks SpanFS improves the performance by up to 73 % relative to Ext4.