Storing multi-rate smoothed vbr objects to MZR disk array

Abstract

As MZR disks have different bandwidths and capacities depending on the zone in use and the performance of continuous media servers is strongly dependent on the block placement scheme for the disks, data placement schemes for traditional CAD disks are not suitable for MZR disks. In this paper, we propose a new block placement algorithm for MZR disk arrays used for continuous media servers. The proposed scheme exploits the bandwidth-saving effect of smoothing VBR data before storing them. To fully utilize characteristics of MZR disks, VBR data are smoothed using multiple smoothing rates (multiplicity is the number of zones of MZR disk). In addition, as the service time of an object in each round is fixed during the lifetime of the stream, it is easy to determine whether the system can provide deterministic service to the new request, which simplifies admission control. Simulation results show that the proposed scheme outperforms previous schemes such as CRT and NCTT.