A Real-Time File System for Constrained Quality of Service Applications

Abstract

The prevalence of multi-tuners, high-definition digital video recorder systems and home networking is increasing the number of simultaneous streams that must be processed by recorder storage devices. Whereas recent hard-disk drives provide enough performance to theoretically handle such workloads, general purpose file systems and I/O schedulers used by operating systems such as Linux do not satisfy the quality of service (QoS) requirements necessary for efficient processing of real-time video streams. In this paper, we introduce the Audio/Video File System (AVFS) composed of a file system and a disk I/O scheduler optimized for handling simultaneous high bit-rate real-time streams. Using a precise QoS measurement method, evaluation results of a Linux implementation of AVFS show that, compared to traditional file systems such as ext3 and JFS, AVFS provides QoS guarantees for real-time streams and more stable performance.