Dynamic access load balancing on the parallel secondary storage

A massively parallel computer handles a massive amount of data with simultaneous access requests from multiple processors, and therefore it must have a large-capacity secondary storage system of very high concurrency. Such a storage system should consist of many disks that are connected in parallel. With such large-scale parallel disk systems, access load balancing is extremely important in order to enhance the effective operation of all disks. In this paper, we propose a parallel file access method named DECODE (Dynamic Express Changing Of Data Entry) which performs dynamic load balancing over all disks according to the load status of each disk. DECODE can achieve load balancing by changing the disk used for writing data to a low-load disk. The efficiency of this method is verified by preliminary performance evaluation using software simulation under various access conditions, by changing the access pattern and the access size. The effect of some of the parameters used in the method is also evaluated.