Abstract: A method, apparatus, article of manufacture, and system are presented for providing a data storage service. An apparatus according to one embodiment of the invention includes a first server coupled to a network and adapted to receive a request for storage from a client computer via the network, and a storage system coupled to the network and adapted to provide a data storage area corresponding to the request for storage, wherein the first server is further adapted to transmit access information associated with the storage area to the client computer, wherein the storage system is further adapted to directly receive an I/O command from the client program for at least one operation relating to the storage area.

Abstract: A data processing system includes a first storage system including a first host and a first storage subsystem. The first host has access to a first copy manager that is operable to manage a data replication operation. A second storage system includes a second host and a second storage subsystem. The second host has access to a second copy manager that is operable to manage a data replication operation. A first communication link is coupled to the first storage system and the second storage system to exchange management information between the first and second storage systems in order to manage the data replication operation. A data transfer path is configured to transfer data stored in the first storage subsystem to the second storage subsystem and replicate the data of the first storage subsystem in the second storage subsystem. The data transfer path is different from the first communication link.

Abstract: A method and apparatus is provided to determine a path from a plurality of predetermined paths between a server system and a storage system in a Storage Area Network by a Fiber Channel Fabric, including one or more Fiber Channel switches. One embodiment, provides a method for selecting a path from a plurality of pre-determined paths between a computer system and a storage system in a Storage Area Network, where the computer system and the storage system are connected together by one or more Fiber Channel switches. The method includes, establishing a first path from the plurality of pre-determined paths between the computer system and the storage system. Next, a status of the first path is determined by the Fiber Channel switch or switches; and a second path from the plurality of pre-determined paths is selected based on the status of the first path. The selection by the Fiber Channel switch is independent of the computer system.

Abstract: A method for handling a remote copy request in a distributed storage includes providing a plurality of primary volumes within a primary storage system that is coupled to a primary host via a first network, the primary storage system being coupled to a secondary storage system via a second network. A first request is selected from a plurality of requests placed in a queue based on priority information associated with the requests. A first path group is selected from one or more path groups that could be used to transmit the request. The first request is transmitted to the secondary storage system using the first path group, the secondary storage system including a plurality of secondary volumes that are paired to the plurality of primary volumes.

Abstract: In a storage system, a logical volume is divided into a plurality of small areas called logical storage devices and only such an area designated by a user is made an object of remote copying or migratory copying. Also, there is provided a unit for forming a logical volume from any logical storage device of any RAID group. Thereby, the reduction of the deterioration in performance at the time of remote copying, the reduction of a storage area to be assigned to a secondary site as a copy destination, the shortening of a time required for migratory copying and the assignment of any area of a logical volume on any RAID group are enabled.

Abstract: A method for failure detection comprises: checking, at a first time, a state of a local volume that is mirrored at a second location; issuing a change state command to the local volume; checking, at a second time, the state of the local volume after a host at the second location issues a change state command; comparing the state of the local volume at the first time and at the second time; and initiating a fail over procedure if the state of the local volume is different at the second time from the first time.

Abstract: A storage control apparatus is coupled to a central processing unit (CPU) and a storage unit to control input/output of data between the CPU and the storage unit. The storage control apparatus has at least two processors coupled to the CPU and the storage unit, a cashe memory (CM) unit for temporarily storing data of the storage unit, a shared memory (SM) unit for storing information concerning control of the CM unit and the storage unit, and a selector coupled to the at least two processors, the CM unit and the SM unit through access paths to selectively apply access requests from the at least two processors to the CM unit and the SM unit.

Abstract: A storage system is provided which preserves data integrity, even when communications line, or similar, errors arise between the local disk system and the remote disk system. When there is no communication line error between the local disk system and the remote disk system, the local disk system sends a time stamp or the write order information with the write data to the remote disk system. This enables the remote disk system to make a copy with data integrity on the disk unit in the remote disk system itself. If there is a communication line error, the remote disk system allocates an empty disk unit and makes a copy with data integrity on the allocated disk unit after the communication line error between the local disk system and the remote disk system is detected.

Abstract: According to the invention, techniques for increasing data transfer performance during read or write of the data stored in Fixed-Block Length format in computer configurations in which a plurality of host computers are connected by a CKD format interface to a disk subsystem. Embodiments include systems, apparatuses and methods. Specific embodiments can provide increased data transfer performance in multiple format disk drive subsystems.

Abstract: In a storage system, a logical volume is divided into a plurality of small areas called logical storage devices and only such an area designated by a user is made an object of remote copying or migratory copying. Also, there is provided a unit for forming a logical volume from any logical storage device of any RAID group. Thereby, the reduction of the deterioration in performance at the time of remote copying, the reduction of a storage area to be assigned to a secondary site as a copy destination, the shortening of a time required for migratory copying and the assignment of any area of a logical volume on any RAID group are enabled.

Abstract: Replication of volumes is facilitated by tools which provide and manage a pool of mirror volumes. Primary (or production) volumes containing user provided data are easily mirrored by volumes selected from the pool. User criteria can be provided to limit the selection of candidate volumes for mirroring.

Abstract: In an information processing system including a central processor for generating commands to process storage data stored and for executing a sequence processing and a storage subsystem including a plurality of storage media for transferring data between the plural storage media according to commands from the central processor, a data recovery method recovers data to a predetermined state upon occurrence of a failure in a sequence of processing executed by the central processor. Before execution of a sequence of processing, the central processor issues to the storage subsystem a saving request to save in the plural storage media a copy of data stored in either one of the storage media used in the sequence of processing. In response to the saving request, the storage subsystem saves a copy of data of the storage media.

Abstract: A storage control apparatus is coupled to a central processing unit (CPU) and a storage unit to control input/output of data between the CPU and the storage unit. The storage control apparatus has at least two processors coupled to the CPU and the storage unit, a cache memory (CM) unit for temporarily storing data of the storage unit, a shared memory (SM) unit for storing information concerning control of the CM unit and the storage unit, and a selector coupled to the at least two processors, the CM unit and the SM unit through access paths to selectively apply access requests from the at least two processors to the CM unit and the SM unit.

Abstract: The present invention provides techniques for managing storage based replication. Specific embodiments provide the capability to make multiple remote copies of information without the necessity of copying information for each pair, for example. One or more remote mirror pairs can be created for disaster recovery, testing, or other purposes.

Abstract: The present invention provides techniques for managing storage based replication. Specific embodiments provide techniques for performing system backup and restoring. In specific embodiments, benefits such as keeping a remote mirror between a primary volume and a secondary volume in operation can be provided. Since the remote mirror is usually used for disaster recovery purposes, where the mirrors must be always in-sync state, being able to take a backup without breaking the remote mirror can help provide a constant duplicate copy of production information in case of emergency, for example. Further, in some embodiments, a user can take backups of more than one generation by setting up two or more secondary volumes (SVOLs) for one primary volume (PVOL).

Abstract: A method of performing an initial copy procedure in a remote copy system, the method including: configuring a network path between a first disk subsystem and a second disk subsystem to increase the speed of data transmission across the network path; configuring the remote copy system for a remote copy operation; performing an initial copy operation to copy data across the network path from the first disk subsystem to the second disk subsystem; and adjusting the network path to reduce the speed of data transmission across the network path. A remote copy system, including: a first disk subsystem located at a first site; and a second disk subsystem capable to be coupled to the first disk subsystem via a network path, with the network path capable to be configured to increase or decrease the speed of data transmission from the first disk subsystem to the second disk subsystem.

Abstract: A storage control apparatus is coupled to a central processing unit (CPU) and a storage unit to control input/output of data between the CPU and the storage unit. The storage control apparatus has at least two processors coupled to the CPU and the storage unit, a cashe memory (CM) unit for temporarily storing data of the storage unit, a shared memory (SM) unit for storing information concerning control of the CM unit and the storage unit, and a selector coupled to the at least two processors, the CM unit and the SM unit through access paths to selectively apply access requests from the at least two processors to the CM unit and the SM unit.

Abstract: The present invention provides techniques for managing data flow over a plurality of connections between primary and remote storage devices. In a representative example embodiment, when the primary storage system copies data to the secondary storage system, it chooses one of a plurality of networks connecting it to the secondary storage system, depending upon a users' policy. Since networks have different characteristics, in terms of, for example, performance, security, reliability, and costs, the user can specify which network(s) are used under various circumstances, i.e., daytime operation, nighttime operation, normal operation, emergency, and so forth. The storage systems comprise a mapping of volumes and ports. When performing copy operations, the primary storage system finds a volume storing the data, and available ports by accessing the mapping. The mappings are based upon policies that are input by a user.

Abstract: A cluster computing system, comprises: a production host group; a standby host group coupled to the production host group by a network; and a remote mirror coupled between the production host group and the standby host group, the remote mirror including a production site heartbeat storage volume (heartbeat PVOL) and a standby site heartbeat storage volume (heartbeat SVOL) coupled by a remote link to the heartbeat PVOL, with the production host group configured to selectively send a heartbeat signal to the standby host group by use of at least one of the network and the remote link.

Abstract: A computer system which has a plurality of computers and a storage device subsystem connected to the plurality of computers. The storage device subsystem has a plurality of storage devices and a plurality of interfaces, through which the subsystem is connected to the computers. One of the plurality of computers has a management means for holding therein data indicative of the storage devices and a connection relationship between the computers and storage device subsystem. Each computer, when wanting a new device, informs the management means of its capacity and type. The management means receives its notification and selects one of the storage devices which satisfies the request. And the management means instructs the storage device subsystem to set predetermined data in such a manner that the computer can access the selected device.