US 5,787,459 A · Distributed disk array architecture

Abstract

A RAID-compatible data storage system which allows incremental increases in storage capacity at a cost that is proportional to the increase in capacity. The system does not require changes to the host system. The control and interface functions previously performed by a single (or redundant) central data storage device controller are distributed among a number of modular control units (MCUs). Each MCU is preferably physically coupled to a data storage device to form a basic, low-cost integrated storage node. One of two bus ports interfaces an MCU with the host computer on a host bus, and the other bus port interfaces an MCU with one or more data storage devices coupled to the MCU by a data storage device bus. The serial interface ports provide a means by which each of the MCUs may communicate with each other MCU to facilitate the implementation of a memory array architecture. The entire data storage array may appear as a single device capable of responding to a single identification number on the host bus, or may appear as a number of independent device. A controlling MCU receives a command and notifies the other MCUs that are involved in a read or write operation. Control of the host bus is transferred from one MCU to the next MCU in sequence so that the data is received by the host computer, or written to each data storage device, in the proper order.

Claims29

Dependent claims

A distributed storage array system configured to be coupled to a host computer having a host bus, comprising:

a plurality of data storage devices for storing and retrieving data in a selected sequence;
a communications link;
and
a plurality of modular control units, each configured to communicate with the host computer directly over the host bus, each modular control unit being coupled to at least one corresponding data storage device and to each other modular control unit by said communications link, wherein:
at least one modular control unit includes a receiver for receiving input/output requests from the host computer directly over the host bus for determining a next data storage device of a sequence of data storage devices involved in responding to a pending one of the received input/output requests;
and
each modular control unit includes a receiver for receiving configuration information from another modular control unit over the communications link separately from communications over the host bus.

4 more elements

A distributed storage array system configured to be coupled to a host computer having a host bus, comprising:

a plurality of data storage devices for storing and retrieving data in a selected sequence;
a communications link;
a plurality of modular control units, each configured to communicate with the host computer directly over the host bus, each modular control unit being coupled to at least one corresponding data storage device and to each other modular control unit by said communications link, wherein:
at least one modular control unit includes a receiver for receiving input/output requests from the host computer directly over the host bus for determining a next data storage device of a sequence of data storage devices involved in responding to a pending one of the received input/output requests;
and
each modular control unit includes a receiver for receiving configuration information from another modular control unit over the communications link separately from communications over the host bus;
and
a cache for caching at least some I/O transactions handled by said modular control units.

5 more elements

Dependencies are inferred from the claim text.

Distributed disk array architecture

Life of this patent

Distributed disk array architecture

Life of this patent

Abstract

Claims29