Disk array system and fault-tolerant control method for the same

Abstract

A disk array system where a plurality of SATA drive enclosures are connected through an FC loop is made capable of continuing to process data even in the event of a fault. When the system is normally operated, a first system controller and a second system controller execute read/write operations from and to disks of a SATA drive enclosure of a disk array via a first interface connector and a second interface connector, respectively, through the FC loop. When an error occurs on a second backend FC loop, the second system controller disconnects itself from the failed second backend FC loop and switches the path to a first backend FC loop which is normally functioning, to access the disk drive.

1 . A disk array system comprising a controller enclosure, one or more serial disk drive enclosures, and a plurality of fibre channel loops respectively connecting the controller enclosure and the plurality of serial disk drive enclosures, wherein the controller enclosure comprises: 
 a communication controller connected to a higher-level device and receives a data from the higher-level device;    a cache memory which is connected to the communication controller and which holds the data communicated between the communication controller and the higher-level device; and    a plurality of system controllers which is connected to the higher-level device and the cache memory and which controls to transfer or receive the data communicated between the higher-level device and the communication controller, to and from the communication controller,    wherein each of the one or more serial disk drive enclosures comprises:    a plurality of port bypass circuits each of which is connected to the fiber channel loops and used to switch a connection of the serial disk drive enclosures of its own to the controller enclosure;    a plurality of interface connectors which is connected to the plurality of system controllers through the plurality of fibre channel loops, and each of which connects a fiber channel interface which is used by the plurality of fibre channel loops and an interface for serial disk drives; a plurality of dual port circuits which is connected to the plurality of interface connectors, respectively, and controls to switch a path to the serial disk drive from the plurality of interface connectors;    a plurality of serial disk drives which is connected to the plurality of port bypass circuits, receives and stores the data transferred from the system controller via the fibre channel loops, the port bypass circuits, the interface connectors, and the dual port circuits; and    an enclosure management processor which is connected to the plurality of interface connectors via the port bypass circuits, and monitors operation of the interface connectors.