Abstract: Apparatus and method for aggregating storage elements. In accordance with various embodiments, a virtual storage space is formed across a plurality of storage elements each comprising an array of data storage devices. A virtual controller comprises a first storage element aggregator (SEA) configured to issue a first command to a selected storage element in response to receipt by the first SEA of a first host command. The virtual controller further comprises a second SEA configured to concurrently issue a second command to the selected storage element in response to receipt by the second SEA of a second host command.

Abstract: A data storage system apparatus and associated method with a virtualization engine connectable to a remote device over a network for passing access commands between the remote device and a storage space. A plurality of intelligent storage elements (ISEs) are configured for replicating data from a first ISE to a second ISE independently of access commands being simultaneously passed between the virtualization engine and the first ISE.

Abstract: Disclosed is a storage system and method that provides multi-path bus and component interconnection and isolation in a data storage system. A plurality of data storage devices in a removable assembly are connected to a fabric that is configurable to connect some or all of the data storage devices (or “drives”) to a drive controller and configurable to isolate one or more data storage devices from the drive controller. Multiple controllers, fabrics, and interconnecting buses may be employed to provide redundancy in the event of a connector, bus, or controller failure. Computer program code operating in a host, interface controller, and/or drive controller configures the fabric to isolate failed devices and may be employed to optimize data transfer rates. Data storage devices may be multi-ported. The fabric may comprise any device or devices capable of configurably interconnecting data storage devices to one or more controllers and may comprise multiplexers, cross point switches, port bypass controllers.

Abstract: Disclosed is a managed reliability storage system and method. A data storage system comprises a plurality of storage devices and at least one storage device controller and may also include additional storage device controllers, one or more host systems, and one or more network connections. Aspects of the invention include reliable data storage formats, planned reliability management, threshold reliability management, and software data recovery. Reliable data formats include fault tolerant storage formats such as RAID and implementations thereof. Planned reliability management includes monitoring of system usage and adjustment of usage reflecting an optimal usage model, scheduled and event driven diagnostic execution and conditional adjustment of operating parameters of storage system components. Software data recovery provides copying and reconstruction of data through redundant data formats including parity, ECC, RLL and others encoding methods.

Abstract: A data storage system adapted to maintain redundant data storage sets at a destination location(s) is disclosed. The data storage system establishes a copy set comprising a source volume and a destination volume. Data written to a source volume is automatically copied to the destination volume. The data storage system maintains a data log that may be activated when the destination volume is inaccessible due to, for example, a malfunction in the destination storage system or in the communication link between the source system and the destination system. I/O commands and the data associated with those commands are written to the data log, and after a destination system becomes available the information in the data log is merged into the destination volume to conform the data in the destination volume to the data in the source volume. The data log competes for disk capacity with other volumes on the system, and log memory is allocated as needed.

Abstract: Methods and systems for managing disk capacity allocated to a data log in a source data storage system during a merge process are disclosed. Data in the data log may be merged into corresponding data on a destination storage system connected to the source data storage system by at least one communication link. In one embodiment a method comprises maintaining a ratio of merge writes out of the data log to writes from a host computer into the data log within a desired range until the write process reaches a predetermined distance from the end of the data log, and quiescing writes from a host computer into the data log until the data log is fully written to the destination storage system.

Abstract: A disaster-tolerant data backup and remote copy system which is implemented as a controller-based replication of one or more LUNs (logical units) between two remotely separated pairs of array controllers connected by redundant links. In the situation wherein an array controller fails during an asynchronous copy operation, the partner array controller uses a ‘micro log’ stored in mirrored cache memory to recover transactions, in order, which were ‘missed’ by the backup storage array when the array controller failure occurred.

Abstract: A data replication system having a redundant configuration including dual Fiber Channel fabric links interconnecting each of the components of two data storage sites, wherein each site comprises a host computer and associated data storage array, with redundant array controllers and adapters. The system employs the grouping of logical units into ‘association sets’, for logging and failover purposes. The concept of association sets allows the system provides for proper ordering of I/O operations during logging across multiple volumes. In addition, association sets are employed by system to provide failure consistency by causing the group of logical units/volumes to all fail at the same time, ensuring a point in time consistency on the remote site.

Abstract: Methods and systems for managing disk capacity allocated to a data log in a source data storage system during a merge process are disclosed. Data in the data log may be merged into corresponding data on a destination storage system connected to the source data storage system by at least one communication link. In one embodiment a method comprises maintaining a ratio of merge writes out of the data log to writes from a host computer into the data log within a desired range until the write process reaches a predetermined distance from the end of the data log, and quiescing writes from a host computer into the data log until the data log is fully written to the destination storage system.

Abstract: A data storage system adapted to maintain redundant data storage sets at a destination location(s) is disclosed. The data storage system establishes a copy set comprising a source volume and a destination volume. Data written to a source volume is automatically copied to the destination volume. The data storage system maintains a data log that may be activated when the destination volume is inaccessible due to, for example, a malfunction in the destination storage system or in the communication link between the source system and the destination system. I/O commands and the data associated with those commands are written to the data log, and after a destination system becomes available the information in the data log is merged into the destination volume to conform the data in the destination volume to the data in the source volume. The data log competes for disk capacity with other volumes on the system, and log memory is allocated as needed.

Abstract: A disaster-tolerant data backup and remote copy system which is implemented as a controller-based replication of one or more LUNs (logical units) between two remotely separated pairs of array controllers connected by redundant links. The system provides a method for allowing a large number of commands to be ‘outstanding’ in transit between local and remote sites while ensuring the proper ordering of commands on remote media during asynchronous or synchronous data replication. In addition, the system provides a mechanism for automatic ‘tuning’ of links based on the distance between the array controllers.

Abstract: A system and method for replicating data between a plurality of storage locations. Each storage location has a controller with a port to a data communication network and a pool of storage. A logical unit (LUN) of storage is implemented at each storage location such that each implemented LUN comprises a substantially complete replica of the data stored in each other LUN. At least two of the controllers at the plurality of storage locations present their implemented LUN as an active device to the one or more host systems for receiving operational data access requests. Preferably, there are three or more storage locations in the system. Preferably, there are three or more storage locations in the system and each storage location can behave as a source location or a destination location for a particular operational data transaction.

Abstract: A multi-cabinet mass storage system with unified management features. The system includes a first reporting group and a second reporting group each having enclosure with processors, such as an environmental monitoring units (EMUs), for generating and transmitting environmental messages pertaining to the particular enclosures. The enclosures are positioned on shelves within cabinets. A bus or cabinet cable links each enclosure to facilitate broadcasting the environmental messages. The environmental messages identify the sending device's reporting group and its physical location within the system. Additional enclosures are included in this reporting group with enclosures of each reporting group located all in one cabinet, in two or more cabinets, and each cabinet may house one, two, or more reporting groups. A network links all of the cabinets to concurrently broadcast the environmental messages throughout the system and allows enclosures in a single reporting group to be positioned in differing cabinets.

Abstract: A data replication management (DRM) architecture comprising a plurality of storage cells interconnected by a fabric. Flexibility in connectivity is provided by configuring each storage cell port to the fabric to handle both host data access requests and DRM traffic. Each storage cell comprises one or more storage controllers that can be connected to the fabric in any combination. Processes executing in the storage controller find a path to a desired destination storage cell. The discovery algorithm implements a link service that exchanges information related to DRM between the storage controllers. The DRM architecture is symmetric and peer cooperative such that each controller and storage cell can function as a source and a destination of replicated data. The DRM architecture supports parallel and serial “fan-out” to multiple destinations, whereby the multiple storage cells may implement data replicas.

Abstract: Methods for allocating memory for logging data written by a host computer to a source virtual disk and for managing memory allocated to a data log, in a data storage system adapted to maintain redundant data storage sets at a destination location(s) are disclosed. The data storage system maintains a data log that may be activated when a destination volume is inaccessible. During the logging process the system implements an adaptive memory allocation algorithm that adjusts the log memory allocation increment as a function of the velocity of logging data written by the host computer(s). Similarly, during a merge process the system implements an adaptive memory deallocation algorithm that deallocates log memory in response to the velocity of logging data written by the host computer(s) and the velocity of merge data transmitted to the remote system. An amount of memory allocated to logging data may be compared with an amount of memory allocated to corresponding user data and, if greater, the data log terminated.

Abstract: A data storage system adapted to maintain redundant data storage sets at a destination location(s) is disclosed. The data storage system establishes a copy set comprising a source volume and a destination volume. Data written to a source volume is automatically copied to the destination volume. The data storage system maintains a data log that may be activated when the destination volume is inaccessible due to, for example, a malfunction in the destination storage system or in the communication link between the source system and the destination system. I/O commands and the data associated with those commands are written to the data log, and after a destination system becomes available the information in the data log is merged into the destination volume to conform the data in the destination volume to the data in the source volume. The data log competes for disk capacity with other volumes on the system, and log memory is allocated as needed.

Abstract: A controller for positioning on a shelf of a cabinet within a mass storage system for controlling communication among device enclosures in a reporting group. The controller includes an interface to a data communication loop linking device enclosures each including disk drives positioned on one or more cabinets. The interface is used to transmit control commands. A cabinet bus interface controller is provided and linked to a cabinet bus in the cabinet to receive enclosure reporting messages from the device enclosures to collect environment information. The cabinet bus interface transmits reporting messages onto the cabinet bus to provide environmental information. The interface controller determines the shelf location of the controller within the cabinet from signals on the cabinet bus and receives the cabinet identifier over the cabinet bus. A processor is linked to the interface controller and functions to create and issue the control commands to the loop interface.

Abstract: A mass storage cabinet having passive device position sensing and including shelves for racking device enclosures. A cabinet bus is linked to the shelves and adapted to provide a unique shelf identifier signal to each of the shelves. The cabinet includes a device providing a cabinet identifier to the shelves. The cabinet bus includes junction boxes having first and second sets of sensing wires and a side connectors linked to the shelves for providing the shelf identifier signal from the first and second sets of sensing wires. To provide a different signal at each junction box, the sensing wires in the first set are moved one position and the sensing wires in the second set are moved one position prior to the connection to an adjacent junction box. An additional sensing wire is linked to the side connectors and grounded and ungrounded at each side connector to alter the signal.

Abstract: A system and method for identifying a failed storage device in a storage system comprising a plurality of storage devices connected by a ring-type network is disclosed. In one embodiment, when a storage device fails, all storage devices on the ring-type network are disconnected to re-establish communication on the ring-type network. An iterative process of connecting a subset of storage devices to the ring-type network and testing communication on the ring-type network is performed until communication on the ring-type network is re-established. Then, individual storage devices are connected to the ring-type communication until the connection of a storage device causes communication on the ring-type network to fail, thereby identifying the failed storage device. In another embodiment, devices in a reporting group are tested on a shelf-by-shelf basis.

Abstract: A storage area network (SAN) controller and method for storing and replicating data between sites in a storage area network in which storage controllers at each site implement storage virtualization. A storage cell is implemented at each site comprising at least one storage controller and a pool of physical storage coupled to the controller. A copy set comprising a logical unit (LUN) of storage, referred to as a member, in each of the storage cells is defined. As operational data transactions are performed against one of the members of a copy set, they are replicated, immediately or after a delay, in each other member of the copy set. As changes are made to dependent attributes such as size of one member of the copy set, the change is replicated in each other member of the copy set automatically. Changes can be made in the independent attributes such as size of each member of the copy set independently of other members of the copy set.