Fiber channel topological structure and method including structure and method for raid devices and controllers

Abstract

System, apparatus and method for interconnecting computer devices define an interconnect topology maximizing performance and device availability in the event of a communication channel failure. Structure and method are particularly relevant and beneficial to a computer RAID disk interconnection topology for Fibre Channel connections to improve RAID array performance and data availability, but is not limited to such RAID systems, and other devices may be interconnected according to the structure and method of the invention. A topology having multiple dual-ported controllers configured in a tube topology is provided for a switchable configuration having a plurality of channels and an plurality of controllers arranged in a tube topology or structure. In the event of a channel failure for this structure, the load will be evenly distributed to the remaining controllers. One embodiment provides a data storage system having a plurality of storage devices each having first and second access ports, a plurality of communication channels, a controller controlling access by the plurality storage devices to the plurality of channels, where at least one of the devices is connected via the first access port to a first one of the channels and via the second access port to a second one of the channels, so that the one device may be accessed by the controller via either the first or second channels channel. Mathematical relationships between the and minimum number of devices for an automatically balanced system and the number of channels are described.