Simplifying Administration through Dynamic Reconfiguration in a Cooperative Cluster Storage System

Cluster Storage Systems where storage devices are distributed across a large number of nodes are able to reduce the I/O bottleneck problems present in most centralized storage systems. However, such distributed storage devices are hard to manage efficiently. In this paper, we examine the use of explicit, component-based (command and data) paths between hosts and disks as a vehicle for performing non-disruptive storage system reconfiguration. We describe the mechanisms necessary to perform reconfigurations and show how they can be used to handle two management tasks: migration between network technologies and rebuilding a disk in a mirror. Our approach is validated through initial performance measurements of these two tasks using a prototype implementation. The results show that on-line reconfiguration is possible at a modest cost