Today's data centers can add storage capacity to almost incomprehensible levels. However, optimal storage capacity utilization or increased capacity does not necessarily equate to increased or optimal performance. In fact, performance upgrades have traditionally been achieved only through adding storage, increasing front-end and back-end links, expanding cache capacity, and/or more efficiently distributing I/O workloads across disk drives. Some of these configuration changes can result in significant performance enhancements. However, clustered block storage technology achieves simultaneous capacity and performance improvement unattainable through normal hardware configuration alternatives. In fact, clustered block storage brings a new dimension of functionality: performance scale-out.

Clustered block storage technology provides scalable storage services with multiple interconnected, yet independent, hardware units called nodes. As storage capacity increases are warranted, data centers meet these needs by introducing another node(s) to the clustered storage system. All new nodes are interconnected and integrated with the existing clustered storage to provide a single system image of all nodes.

Nodes of a clustered block storage system often include x86-class servers consisting of multi-core processors, memory, and storage. A data center could potentially have hundreds of interconnected yet independent nodes.

Clustered block storage is often likened and compared to grid storage. While grid storage does operate as a single storage system, it usually requires geographically dispersed storage units. In contrast, clustered block storage need not be geographically dispersed. Even though IT disaster-recovery policies might mandate off-site replication of a clustered block storage system, the existence of two locations alone does not mean the storage systems are operating as a single unit. As such, all grid storage can be described as clustered block storage but not all clustered block storage systems are grid storage.

SANstor is offering three clustered storage options to its clients: Exanodes, CleverSafe, and Digi-Data.