Apollon: File System Level Support for QoS Augmented I/O

Next generation information appliances are required to handle real-time audio/video playback and in the mean time should be able to handle text based requests such as database search, file recording, etc. Although several techniques are presented to address this problem, most of them are rather theoretical to be employed into practical systems as they are. In this paper, we present our experience in developing the file system which can efficiently handle mixed workload. To this end, we develop practical I/O scheduling mechanism to prioritize the incoming disk I/O requests: deadline-driven I/O scheduler and admission control module. We also discuss some issues on QoS enhanced I/O semantics. The proto-type file system Apollon is developed on Linux Operating System. Compared to legacy system, Apollon exhibits superior performance in guaranteeing the QoS requirement of real-time requests.