Automatic reconfiguration of an autonomous disk cluster

Recently, storage-centric configurations, such as NAS and SAN architectures, have attracted attention in advanced data processing. For these configurations, scalability, flexibility, and availability are key features, and central control is unsuitable. We propose autonomous disks to enable distributed control in the storage-centric configurations. Autonomous disks configure a cluster in a network, and implement the above key features using ECA rules with a distributed directory. The combination of the rules and directory also manages load distribution, and has a capability of reconfiguring the cluster automatically. We focus on the cluster reconfiguration, utilizing the skew handling mechanism. Autonomous disks adopt a multi-phase synchronization protocol with a dynamic coordinator for reconfiguration, apart from data migration. They allow the usual operations to be accepted during reconfiguration. We also report preliminary results of our experimental system. They indicate that synchronization cost is adequately acceptable.