Performance evaluation of the Stony Brook Video Server

Stony Brook Video Server (SBVS) is an Ethernet based video server that employs only off the shelf PC components and is capable of guaranteeing real time delivery of digital video streams from the server's disk subsystem, through a shared local area network, to an end user's display. SBVS integrates a real time software based disk array with a Real Time Ethernet Protocol, RETHER to provide end to end bandwidth guarantee. The paper reports the results of a detailed performance evaluation study of SBVS, specifically the efficiency with which SBVS utilizes the hardware capabilities of Fast Ethernet and SCSI disks in the context of video servers, and the overhead of integrating real time I/O and network components into a complete system. Two sets of experiments were performed: (1) experiments that measure the maximum performance of individual I/O and network hardware when operating based on the algorithms used in SBVS; and (2) experiments that evaluate SBVS as a whole in terms of the maximum number of video streams that can be supported under varying stream rates, disk retrieval sizes, and number of network interfaces. The major results are that SBVS-2, a Pentium-90 PC with a four-drive disk array and a single 100 Mbps Ethernet, can support up to a maximum of 45 simultaneous MPEG-1 (1.5 Mbits/sec) streams, and that using a six-drive array and serving two 100 Mbps Ethernet segments, SBVS can support up to a maximum of 65 MPEG-1 streams, with CPU being the performance bottleneck.