XIV® Architecture

The IBM XIV Storage System is built as a grid-based storage system of independent modules, connected in any-to-any topology by means of massively paralleled, non-blocking Gigabit Ethernet.

The modules are implemented using off-the-shelf, Intel-based servers within a customized, Linux-based architecture, and are interconnected over redundant Gigabit Ethernet switches. The modules act jointly as a large data grid devoid of a common backplane. The grid is managed by sophisticated distributed algorithms and delivers enterprise-class performance, reliability, and functionality.

The XIV system is built modularly, from the following components:

• Data modules. The data modules are Intel-based servers with a large number of disks. The modules store the data and perform all advanced storage functionality, such as redundancy, snapshots, and caching. Some of the data modules also contain interface connectivity; these are responsible for accepting host I/O commands (via FC or iSCSI) and forwarding them to the appropriate data module.
• Gigabit Ethernet switches. The switches are the interconnect between all the data and interface modules.
• UPS units. The UPS units ensure that the system has enough time to de-stage all cached data upon a power outage.

The XIV system provides a management function that handles all system-wide management functions: allocating new volumes, etc. In keeping with IBM XIV's streamlined, standardized approach to architecture, the function does not have its own dedicated hardware. Instead, it runs on one of the standard modules and, in the event of failure of that module, automatically restarts on another module.