Design and evaluation of a generic software architecture for on-demand video servers

High-bandwidth and real-time constraints for supporting concurrent video ac cesses make generic software architecture design for high-performance on-de mand video servers challenging. This challenging task can be even more comp licated when we consider that a generic software architecture should be app lied to different hardware platforms. In this paper, we introduce the desig n, implementation, and evaluation of a generic software architecture for on -demand video servers. We describe different key components on controlling the storage and network devices within the server. The interactive collabor ations between these software components are also illustrated, The experime ntal results indicate a very promising direction on exploring the right com binations of these software components. The server is, thus, able to increa se the number of concurrent video accesses with the same hardware configura tion. For instance, with the right combinations, the system achieved about 80 percent of the storage system bandwidth of four disks, about 70 percent of the storage system bandwidth of six disks, and generally reached the max imal achieved SCSI bandwidth when eight disks are used over two SCSI buses (i.e., four disks on each SCSI bus). Our research and experimental results are based on video servers currently under construction across a variety of hardware platforms, including SMP, DMP, and clusters of PC or workstations . The most-advanced prototype server is based on an SGI shared-memory multi processor with a mass storage system consisting of RAID-3 disk arrays. With all the enabling/management schemes, we were able to further investigate i nteresting research issues by considering the user's access profiles for ta king advantage of popular video titles. The results were significant, with a range of 60 percent improvement given a 512 Kbyte block size; In addition to the experimental results, theoretical performance models were also deve loped that closely match to our collected experimental results.