Hewlett-packard Development Company, L.p.

Seagate Technology Incorporated

Robert George Bean

Clark Edward Lubbers

Randy L Roberson

David William Thiel

James Michael Reuter

Richard Fitzhugh Wrenn

Anuja Korgaonkar

James Michael Reiser

Wayne Umland

R Brian Schow

Keith D Woestehoff

Mark A Gaertner

Richard Perham Helliwell

Paul William Burnett

Jesse L Yandell

Robert J German

Bruce Allen Bicknell

Ayman Mohammad Ghanem

Masami Y Hua

Robert Brinham Trace

A redundant data storage system is provided comprising a first controller with top-level control of a first memory space and a second controller with top-level control of a second memory space different than the first memory space. The system is adapted for asynchronously reflectively writing state information by the first controller to the second memory space; alternatively the system is adapted for asynchronously reflectively writing state information by the second controller to the first memory space. A method is provided for operating the redundant data storage system by resolving any inconsistency between the existing state information and a modified state information associated with a state information change request, and for switching control in the redundant data storage system between the controllers.

Failover control of dual controllers in a redundant data storage system

Apparatus and associated method that stores first metadata only at the same addressable storage location of a computer readable medium as that where associated first user data is stored, and afterward satisfies a read request for the first user data by retrieving the first user data from the addressable location of the computer readable medium where the first metadata is stored if the first metadata has a first value, and by reconstructing the first user data from other metadata stored at another addressable location of the computer readable medium than where the first metadata is stored if the first metadata has a second value.

Data reliability bit storage qualifier and logical unit metadata

A management interface for a virtualized storage system including a virtualized logical disk object representing a virtual storage container, wherein the logical disk is an abstract representation of physical storage capacity provided by plurality of physical stores. A virtual disk object represents a virtual storage container. The virtual disk object is an abstract representation of one or more logical disk objects, the virtual disk object including an exposed management interface. Wherein the virtual disk object is managed through the management interface to select the one or more logical disk objects represented by the virtual disk object.

System and method for interfacing with virtual storage

An apparatus and associated method are provided for performing a storage transaction associated with a network I/O command by employing an ASIC having an interconnect selectively coupling a plurality of dedicated purpose function controllers in the ASIC to a policy processor via a list manager in the ASIC communicating on a peripheral device bus to which the policy processor is connected.

Processor partnering in a storage system

A method is provided for storing and retrieving data in a network-attached data storage device by a cooperatively multitasking real time operating system configured to execute datapath routines and a general purpose operating system kernel configured to communicate with the network.

Context-free data transactions between dual operating systems embedded within a data storage subsystem

A data storage subsystem in a distributed storage system having a plurality of predictive failure analyzing data storage devices. The subsystem furthermore has a circuit that is responsive to a predicted failure indication by a data storage device in relation to predetermined rules stored in memory for deterministically initiating a preventive recovery either by a data recovery procedure in the data storage device or by a fault tolerance storage arrangement in the subsystem.

Deterministic preventive recovery from a predicted failure in a distributed storage system

A system and method for high performance multi-controller processing is disclosed. Independent Network storage controllers (NSCs) are connected by a high-speed data link. The NSCs control a plurality of storage devices. connected by a Fiber Channel Arbitrated Loop (FCAL). To provide redundancy, for a given logical unit of storage one NSC will function as the primary controller and the other NSC will function as the primary controller and the enhance the efficiency of command-response data transfers between NSCs, mirror memory is correlated with primary memory and named resources are used for command-response data transfers. Methods are disclosed to provide for efficient active mirroring of data.

Multi-controller write operations

The present invention provides a method for copying data through a virtualized storage system using distributed table driven (I/O) mapping. In a system having a virtual disk (the 'original disk'), a persistent mapping table for this virtual disk exists on a controller, and volatile copies of some or all entries in this mapping table are distributed to one or more more mapping agents. The method of the present invention creates a new virtual disk mapping table that has the exact same entries as the mapping table as the original virtual disk. The new snapshot disk then shares the same storage as the original disk, so it is space efficient. Furthermore, creating new snapshot disk involves only copying the contents of the mapping table, not moving data, so the creation is fast. In order to allow multiple virtual disks to share storage segments, writes to either the original virtual disk or the snapshot copy cannot be seen by the other. Therefore, in addition to simply copying the mapping table, both the original and snapshot disk mapping table must also cause writes to these disks to be handled specially. Finally, any changes to the original disk mapping table stored in the controller must be coordinated with the volatile copies stored in the mapping agent in such a way so that all hosts see a consistent view of that disk.

Generating updated virtual disks using distributed mapping tables accessible by mapping agents and managed by a centralized controller

A storage system permits virtual storage of user data by implementing a logical disk mapping structure that provides access to user data stored on physical storage media and methods for generating point-in-time copies, or snapshots, of logical disks. A snapshot logical disk is referred to as a predecessor logical disk and the original logical disk is referred to as a successor logical disk. Creating a snapshot involves creating predecessor logical disk mapping data structures and populating the data structures with metadata that maps the predecessor logical disk to the user data stored on physical media. Logical disks include metadata that indicates whether user information is shared between logical disks. Multiple generations of snapshots may be created, and user data may be shared between these generations. Methods are disclosed for maintaining data accuracy when write I/O operations are directed to a logical disk.

Point in time storage copy

The present invention provides a system and method for creating virtualized storage in a storage area network using distributed table-driven input/output mapping. The present invention distributes the virtualization mapping in multiple parallel, mapping agents that are separate from a controller. This allows the performance-sensitive mapping process to be parallelized and distributed optimally for performance, while the control of the mapping may be located in a controller chosen for optimal cost, management, and other implementation practicalities. The mapping agents store the virtual mapping tables in volatile memory, substantially reducing the cost and complexity of implementing the mapping agents. The controller is responsible for persistent storage of mapping tables, thereby consolidating the costs and management for persistent mapping table storage in a single component. Distributed virtualization also allows the controller to manage multiple virtual disks used by multiple host systems, and allows a single virtual disk to be shared by multiple host systems. The mapping agents preferably do not interact only with other mapping agents, thereby improving the scalability of the virtual storage system and the virtual storage system's tolerance of component failures.

Architecture for parallel distributed table driven I/O mapping

A system and method for high performance multi-controller processing is disclosed. Independent Network storage controllers (NSCs) are connected by a high-speed data link. The NSCs control a plurality of storage devices connected by a Fiber Channel Arbitrated Loop (FCAL). To provide redundancy, for a given logical unit of storage one NSC will function as the primary controller and the other NSC will function as a mirror controller. To enhance the efficiency of command-response data transfers between NSCs, mirror memory is correlated with primary memory and named resources are used for command-response data transfers. Methods are disclosed to provide for efficient active mirroring of data.

High performance multi-controller processing

System and method for generating point in time storage copy

Systems, methods and software for implementing a virtualized storage system. Physical storage is carved into units called physical segments. Logical storage is implemented in atomic logical units called RStores comprising a range of virtual address space that when allocated, is bound to a particular group of PSEGs. RStores preferably implement a selected level of data protection. A pool of physical storage devices is carved into redundant storage sets. A plurality of RStores make up a logical disk that is presented to a user. Storage access requests expressed in terms of logical disk addresses are mapped to PSEGs containing data represented by the logical addresses through a split-directory representation of the logical unit.

System and method for atomizing storage

A system for moving physically stored data in a distributed, virtualized storage network is disclosed. A group of data sets is written to a first storage device as part of a write operation such as migration. A plurality of storage devices partially filled with data are designated as substitutes. The write operation to the first storage device is suspended upon receiving a request to read a data set stored in the first storage device, such as occurs in a recall operation. A second storage device is then selected from the plurality of substitute storage devices. The write operation is continued by writing data sets from the group of data sets included in the write operation that were not written to the first storage device to the selected second storage device. The requested data is then read from the first storage device. After data has been read from the first storage device, the first storage device may be designated as a substitute storage device so that the partially filled first storage device may be selected for continuing write operations. Data sets from substitute storage devices may be transferred or merged into a lesser number of storage devices during recycle operations to prevent the number of substitute storage devices from increasing beyond a predetermined limit or goal. Recycling operations in which data sets from different storage devices are transferred or merged may be performed by building a first queue including a list of filled tapes ordered according to the least amount of valid data and a second queue including all unassociated partially filled storage devices ordered by the amount of available storage space, and merging.

Growing community of inventors

Monument, CO, United States of America

Robert George Bean