International Business Machines Corporation

Mylex Corporation

Krishnakumar Rao Surugucchi

James Lee Hafner

Karl Allen Nielsen

Bulent Abali

Robert Akira Kubo

Mohammad Banikazemi

David Frank Mannenbach

David Ray Kahler

James A O'Connor

Dan Edward Poff

Richard B Stelmach

Timothy Joseph Chainer

Steven Robert Hetzler

Binny Sher Gill

Carl Evan Jones

Kaladhar Voruganti

Prasenjit Sarkar

Jaishankar Moothedath Menon

Lawrence Yiumchee Chiu

Mohamad H El-Batal

Daniel Felix Smith

Wendy Ann Belluomini

Veera W Deenadhayalan

Bruce M Cassidy

Patrick Cozzi

Yoshihiro Fujie

Venu Nayar

James A O'Conner

Geeta George

Govindaraju Gnanasivam

Kailash

Daniel Edward Poff

Nicholas Lloyd Armstrong-Crews

Patrick Randolph Eaton

Thomas Sing-Klat Liong

An apparatus comprises a storage controller coupled to at least one multi-region storage device. The at least one multi-region storage device comprises two or more storage regions, the two or more storage regions comprising a first storage region associated with a first set of failure characteristics and at least a second storage region associated with a second set of failure characteristics different than the first set of failure characteristics. The storage controller is configured to replicate in the second storage region at least a portion of data that is stored in the first storage region.

Storing data in multi-region storage devices

Protection from uncorrectable media errors are provided for a RAID-configured storage system by a technique in which c redundancy information sectors are associated with n data information sectors. The n data sectors and c redundancy information sectors are then written as a single segment on a single storage unit. The RAID-configured storage system can be configured, for example, as a RAID 6 storage system, a RAID 5 storage system, a RAID 51 storage system, a RAID 3+3 storage system or a RAID N+3 storage system. The redundancy information can be based on a Reed-Solomon code, an XOR-based code, or one-dimensional parity.

Method to protect data on a disk drive from uncorrectable media errors

Provided are a method, system, and article of manufacture for error checking addressable blocks in storage. Addressable blocks of data are stored in a storage in stripes, wherein each stripe includes a plurality of data blocks for one of the addressable blocks and at least one checksum block including checksum data for the addressable block. A write request is received to modify data in one of the addressable blocks. The write and updating the checksum are performed in the stripe having the modified addressable block. An indication is made to perform an error checking operation on the stripe for the modified addressable block in response to the write request, wherein the error checking operation reads the data blocks and the checksum in the stripe to determine if the checksum data is accurate. An error handling operation is initiated in response to determining that the checksum data is not accurate.

Error checking addressable blocks in storage

Embodiments of the invention enable a storage cache, comprising flash memory devices, to have direct block access to the flash such that the physical block addresses are presented to the storage system's cache layer, which thereby controls the storage cache data stream. An aspect of the invention includes a caching storage system. The caching storage system comprises a plurality of flash memory units organized in an array configuration. Each of the plurality of flash memory units includes at least one flash memory device and a flash unit controller. Each flash unit controller provides the caching storage system with direct physical block access to its corresponding at least one flash memory device. The caching storage system further comprises a storage cache controller. The storage cache controller selects physical block address locations (within a flash memory device) to be erased where data are to be written, issues erase commands to a flash unit controller corresponding to the selected physical block address locations, and issues page write operations to a set of erase blocks.

Storage system cache using flash memory with direct block access

Provided are a method, system, and article of manufacture for error checking addressable blocks in storage. Addressable blocks of data are stored in a storage in stripes, wherein each stripe includes a plurality of data blocks for one of the addressable blocks and at least one checksum block including checksum data derived from the data blocks for the addressable block. A write request is received to modify data in one of the addressable blocks. The write and updating the checksum are performed in the stripe having the modified addressable block. An indication is made to perform an error checking operation on the stripe for the modified addressable block in response to the write request, wherein the error checking operation reads the data blocks and the checksum in the stripe to determine if the checksum data is accurate. An error handling operation is initiated in response to determining that the checksum data is not accurate.

A computer implemented method, apparatus, and computer usable program product for managing redundant array of independent drives. In response to a failure of a hard disk in a first RAID array, the process calculates an amount of free capacity available across a set of remaining hard disks in the first RAID array. The set of remaining hard disks comprises every hard disk associated with the first RAID array except the failed disk. In response to a determination that the amount of free capacity is sufficient to re-create the first RAID array at a same RAID level, the process reconstructs the first RAID array using an amount of space in the set of remaining drives utilized by the first RAID array and the free capacity to form a new RAID array without utilizing a spare hard disk.

Storage redundant array of independent drives

A set of disks in a plurality of disk arrays are configured to have one or more spare partitions. Upon detecting a faulty disk in a faulty array, the method involves the steps of: (a) migrating data in the faulty array containing the faulty disk to one or more spare partitions; (b) reconfiguring the faulty array to form a new array without the faulty disk; (c) migrating data from one or more spare partitions in the set of disks to the reconfigured new array; (d) monitoring to identify when overall spare capacity falls below a predetermined threshold; and when the predetermined threshold is exceeded, scheduling a service visit for replacement of the failed disks.

Method for providing deferred maintenance on storage subsystems

A system (and method) for determining reconstruction formulas for partial strip reconstruction in a storage system in which a plurality of lost strips have been detected, includes using a combination of a direct reconstruction method and a sequential reconstruction method.

System and method for reconstructing lost data in a storage system

Methods are provided for detecting and correcting dropped writes in a storage system. Data and a checksum are written to a storage device, such as a RAID array. The state of the data is classified as being in a 'new data, unconfirmed' state. The state of written data is periodically checked, such as with a timer. If the data is in the 'new data, unconfirmed' state, it is checked for a dropped write. If a dropped write has occurred, the state of the data is changed to a &#x201c;single dropped write confirmed&#x201d; state and the dropped write error is preferably corrected. If no dropped write is detected, the state is changed to a &#x201c;confirmed good&#x201d; state. If the data was updated through a read-modified-write prior to being checked for a dropped write event, its state is changed to an &#x201c;unquantifiable&#x201d; state.

Detection and correction of dropped write errors in a data storage system

A bladed storage servicing system comprising a RAID layout facilitates the removal of one or more functional storage devices in a tray of the bladed storage subsystem in order to service a failed storage device. Upon removal of the tray from the bladed storage subsystem, the system designates the functional storage devices on the tray as temporarily removed. The system logs writes to the removed functional storage devices so that the functional storage devices can be returned to consistency when replaced in the bladed storage subsystem. The system manages reads to the removed functional storage devices through reconstruction from active storage devices in the bladed storage subsystem. Upon reinsertion of the tray in the bladed storage subsystem, the system verifies the identities of the functional storage devices and resynchronizes the functional storage devices to ensure data consistency.

Method for servicing storage devices in a bladed storage subsystem

A system, program storage device, and method of optimizing data placement on a storage device, the method comprising establishing a specified time constraint for which the storage device is to delete data stored thereon; dividing a data object into a plurality of data bits; programming a block of data and the data bits with a logic operand if the storage device is incapable of deleting the data within the specified time constraint; creating an encoded block of data from the programmed block of data and the data bits; organizing the encoded block of data and the data bits in the storage device according to data deletion requirements; and removing the data bits from the storage device if the data bits are organized within a specified data deletion requirement, wherein the data bits are removed using a data shredding process, and wherein the logic operand comprises an exclusive-or (XOR) operator.

System and method for fast, secure removal of objects from disk storage

The present invention describes a method and system for interfacing a plurality of device controllers to an array of data storage devices by serial connection. The device controllers are coupled to a serial interface by a bus and the devices of the storage array are coupled to the serial interface by a serial connection. The serial interface receives controller signals through the bus and multiplexes the signals onto the serial connections of the storage array. Arbitration between the various device controllers seeking access to the storage array is resolved through bus protocol and through drive based reserve/release registers in the serial interface processor.

Serial interface for a data storage array

A method, system and apparatus for providing inter-connective access of a plurality of controllers to a plurality of serial storage devices are provided. Serial storage devices are provided with a serial operative connection to a data communication bridge. The bridge is operatively coupled to a plurality of controllers. The plurality of controllers is provided concurrent targeted connections to the set of serial storage devices. In one embodiment, InfiniBand&#xae; technology further increases the scalability and enhances the reliability of a data communication system provided with a plurality of (S-ATA) storage devices. The reliability of the data communication system is enhanced because if one controller should fail, another controller may still achieve and maintain access to the plurality of serial storage devices.

Method and apparatus for enhancing reliability and scalability of serial storage devices

Apparatus and methods are provided for efficiently implementing logical-device reservations in a cluster computer system. The apparatus includes cooperating controllers programmed in firmware around a distributed reservation table. The apparatus manages access to a logical device, with first and second nodes with respective bus controllers communicatively coupled to each other and to a logical device by means of a bus. The first controller receives a request to reserve the logical device and, in response, communicates a reservation request for the logical device over the bus to the second controller for execution by the second controller. In response to the communicated reservation request, the second controller reserves the logical device for the first node.

Apparatus and method for implementing raid devices in a cluster computer system

Structure, method, and computer program for an explicitly tunable device controller. Method supports high-performance I/O without imposing additional overhead during normal input/output operations. Tuning is performed during explicit pre-I/O operation phase. In one embodiment, invention provides a method for tuning device controller operating characteristics to suit attributes of a data stream in which the method comprises: monitoring a data stream and collecting attributes of the monitored data stream; generating performance metrics of the data stream based on the collected attributes and a plurality of different assumed device controller configurations; comparing expected performance of the plurality of different device controller configurations for effectiveness with a future data stream having similar data stream type attributes to the monitored data stream; and selecting device controller characteristics to provide an effective match between the data stream type and the device controller configuration. In one embodiment, the controller configuration is adjusted automatically and dynamically during normal I/O operations to suit the particular input/output operation encountered. Configuration information may be selected for example, from such parameters as data redundancy level, RAID level, number of drives in a RAID array, memory module size, cache line size, direct I/O or cached I/O mode, read-ahead cache enable or read-ahead cache disable, cache line aging, cache size, or combinations thereof. A storage device controller, such as a RAID controller, implementing the inventive method in computer program software or firmware is also provided as are computer system having a host computer coupled to a storage system through the inventive controller.

Growing community of inventors

Fremont, CA, United States of America

Krishnakumar Rao Surugucchi