Virtual large-scale disk system for PC-room

Abstract

There are many PCs in a PC room. For example, there are 500 PCs in our University. Each PC has a HDD, which is typically not full. If the disk utilization is 50% and each PC has a 240GB HDD, there is 60TB (500×120GB) free disk space. The total size of the unused capacity of these HDDs is nearly equal to the capacity of a file server. Institutions, however, tend to buy expensive appliance file servers. In this paper, we propose an efficient large-scale storage system that combines client free disk space. We have developed a java-based toolkit to construct a virtual large-scale storage system, which we call VLSD (Virtual Large-scale Disk). This toolkit is implemented in Java and consists of RAID (Redundant Arrays of Inexpensive/Independent Disks) and NBDs (Network Block Device). Using VLSD, we show how to construct a large disk that consists of multiple free spaces distributed over networks. VLSD supports typical RAID and other utility classes. These can be combined freely with one another. © Springer-Verlag Berlin Heidelberg 2007.