Agios: Application-Guided I/O Scheduling For Parallel File Systems

In this paper, we improve the performance of server-side I/O scheduling on parallel file systems by transparently including information about the applications' access patterns. Server-side I/O scheduling is a valuable tool on multi-application scenarios, where the applications' spatial locality suffers from interference caused by concurrent accesses to the file system. We present AGIOS, an I/O scheduling library for parallel file systems. We guide scheduler's decisions by including information about the applications' future requests. This information is obtained from traces generated by the scheduler itself, without changes in application or file system. Our approach shows performance improvements under different workloads of 46.3% on average when compared to a scenario without an I/O scheduler, and of 25.1% when compared to a scheduler which does not use information about future accesses.