Abstract:
Failover processing in storage server system utilizes policies for managing fault tolerance (FT) and high availability (HA) configurations. The approach encapsulates the knowledge of failover recovery between components within a storage server and between storage server systems. This knowledge includes information about what components are participating in a Failover Set, how they are configured for failover, what is the Fail-Stop policy, and what are the steps to perform when "failing-over" a component.
Abstract:
A mechanism to support remote mirroring of storage devices by data storage systems (16a-16d) in a one-to-many switched environment. Each data storage system includes a disk director that is adapted to control at least one device group that is supported in a mirrored configuration with a corresponding device group controlled by one of the other data storage systems. For each device group and corresponding device group, there are first ports associated with the device group and second ports associated (34a-34h) with the corresponding device group. A switch element is adapted to connect one of the first ports to at least one of the second ports so that data may be exchanged between the ports for each device group and corresponding device group. The disk director selects which first port is to be connected to which second port via the switch element in the establishment of a logical link. Thus, each port connected to the switch is capable of achieving multiple connections to multiple destinations for increased connectivity, redundancy and performance (load balance) without additional hardware.
Abstract:
A computer system may include one or more hosts and a plurality of data storage devices for providing multihop system calls. The data storage devices are interconnected and also connected to the one or more hosts. Each data storage device classifies a data operation as a system call, a remote system call, or a multihop system call. Also described is a multipath multihop system call in which one or more communication paths may be selected using predetermined and/or dynamic communication path selection techniques. The number of communication paths determined may be in accordance with parameters that are included in a multipath multihop system call, tunable system parameters, or a combination of the foregoing.
Abstract:
A method and apparatus for performing fault-tolerant network computing using redundant communications modules. The apparatus comprises a pair of network appliances coupled to a network. The appliances interact with one another to detect a failure in one appliance and instantly transition operations from the failed appliance to a functional appliance. Each appliance monitors the status of another appliance using multiple, redundant communication channels are formed using a plurality of network interface cards.
Abstract:
A data storage system having a plurality of disk drives. Each one has a pair of ports. A pair of directors controls the flow of data to and from the disk drives. A first and second fibre channel port by-pass selector section are provided. The first fibre channel selector section includes: a input/output port coupled to a first one of the directors; and, a plurality of output/input ports connected between a first one of the ports of the plurality of disk drives through a first plurality of fibre channel links. The first fibre channel port by-pass selector section is adapted to couple the first one of the directors serially to one, or ones, of the first ports of the plurality of disk drives through a first fibre channel selectively in accordance with a control signal fed to the first fibre channel by-pass selector section. The first fibre channel includes one, or more, of the first plurality of fibre channel links. The second fibre channel port by-pass selector section is similarly configured.
Abstract:
It has been demanded to develop a large scale memory device system operable without interruption. Further, in order to cope with the recent trend toward open systems, scalability of performance and capacity is needed. Conventionally, internal buses, such as the ones which connect the channel I/F section to the shared memory section and the disc I/F section to the shared memory section, are mounted on one platter, and the package of the channel I/F and so forth are mounted thereon. When the internal buses have failed, the operation of the whole system must be stopped. There is another problem that the performance of the internal buses is fixed. A disc array controller according to the invention comprises an interface platter on which a channel interface section and a disc interface section are mounted, a memory platter on which a shared memory section is mounted, and a cable which connects the interface platter to the memory platter in order to solve the above problems.
Abstract:
A mass storage/retrieval module for controlling the storage and retrieval operations of massive amounts of data in peripheral devices such as tape, disk, optical, etc. (70) provides for a buffer memory system (24c, 24d) in each of the interface control modules (8c, 8d) which permit simultaneous and concurrent writing to buffer storage (24c, 24d) and reading out of buffer storage through multiple ports (P0, P1, P2, P3) for high rates of data transfer operations. Redundancy and high reliability is provided in that each module of the system has dual busses (6a, 6b) and live replacement units such that, upon failure, an alternate unit can carry the circuitry requirements until the failing unit has been replaced.
Abstract:
A fault tolerant network fileserver system includes a plurality of nodes connected to a network communication link. A primary fileserver node stores files from a plurality of the nodes and a backup fileserver node stores copies of files from the primary fileserver. In an improved fileserver system, the primary and backup fileservers are connected to a dual ported memory for communicating information between the fileservers. The primary fileserver writes data files to the dual ported memory and interrupts a processor within the backup fileserver to notify it that the dual ported memory contains data. In response to the interrupt, the processor within the backup fileserver reads the data from the dual ported memory and writes it to a storage device within the backup fileserver. In a similar manner, the dual ported memory is used for passing control messages between the primary and backup fileservers. The dual ported memory includes semaphore locations for arbitrating between competing requests by the backup and primary fileservers for access to the same location in the dual ported memory.
Abstract:
A method and apparatus for controlling data flow between a computer (10) and a group of memory devices (18A-18F) arranged in a particular logical configuration. The system includes a group of first level controllers (12A, 12B) and a group of second level controllers (14A, 14B). The first level controllers and the second level controllers work together such that if one of the second level controllers fails, the routing between the first level controllers and the memory devices is switched to a properly functioning second level controller without the need to involve the computer in the rerouting process. The logical configuration of the memory devices remains constant. The invention also includes switching circuitry (16) which permits a functioning second level controller to assume control of a group of memory devices formely primarily controlled by the failed second level controller. In addition, the invention provides error check and correction (Figure 10) as well as mass storage device configuration circuitry.