Data Placement of a RAID Based on Zone Disks

Abstract

Due to the characteristics of MZR disks, such as variable transfer rates and capacities in different zones, the file placement has great effects on the system performance. First, according to the physical zones of zone disks, we can partition a disk array into several regions. For each region, we give a range of maximum number of data striping respectively. Then considering the factors such as file characteristics and popularity levels, the placement constraints for files are presented. According to the constraints and current disk array configuration, a file placement algorithm is proposed to allocate appropriate disk locations for files. Through the simulation, we found that the dropping rate of real-time file requests in our method is explicitly less than those in the other two placement strategies. Furthermore, we also observed that more available disk spaces in high-bandwidth regions, after using our method, make our method more elastic than the PVW placement in the future when placing high QoS files such as MPEG2.