Abstract: To provide a staging method capable of detecting an error in data read from a disk device during staging, a disk array control apparatus 100 includes a data read unit 101 for reading data, a first reference data generation unit 102 for generating first reference data from the read data, a second reference data generation unit 103 for similarly generating second reference data, a true-false determination unit 104 for determining whether or not the data read by the data read unit 101 is correct, and a data write unit 105 for writing data to cache memory.

Abstract: A device adaptor that controls a disk, wherein a storage area is divided into a plurality of blocks, detects a block that includes a read error. Next, the device adaptor detects a write omission in blocks that are within a predetermined range from the block that includes the read error. To be specific, the device adaptor reads data from the blocks that are in the vicinity of the block that includes the unrecovered read error in a suspect disk. Next, the device adaptor reads from a redundant disk, data of a block that corresponds to the block that includes the unrecovered read error (data of block “B” in an example shown in FIG. 1) and compares the read data to the data read from the suspect disk to detect the write omission.

Abstract: When a write-back request for writing back new data in a cache memory to disk devices forming a redundant configuration of RAID is generated, a write-back processing unit, reserves a parity buffer area in the cache memory, generates new parity, and then, writes the new data and the new parity to the corresponding disk devices. When an error in which the consistency of RAID is broken occurs in a plurality of the disk devices upon write performed by the write-back processing unit, a recovery processing unit reserves, in the cache memory, a cache stripe area storing data of the entire stripe including the new data which is to be written back, and causes the cache control unit to manage it.

Abstract: A RAID control apparatus comprises at least a cache memory; an update information management table for storing update information; an update information storage unit for storing, in the update information management table, update information by detecting a data update; a reference value generation unit for generating a reference value expressing a load of a write back processing by using a Small Write method and a Read & Bandwidth Write method based on the update information; a write method determination unit for determining a write method according to the reference value and a write unit for carrying out a write processing, in order to provide a write back method for a RAID apparatus capable of improving a processing speed at the time of updating even in the case of including the processing of updating a part of data stripes.

Abstract: The present invention has been made to obtain a magnetic disk apparatus and the like capable of using a patrol region in the magnetic disk to detect a location in need of maintenance in hardware equipment around the magnetic disk in a separate manner from the disk itself and thereby avoiding useless replacement and operating the magnetic disk apparatus at low cost. In a preventive maintenance detection for a magnetic disk apparatus having a patrol function that uses a patrol region in the magnetic disk to determine the presence/absence of the need of preventive maintenance, a data pattern for detecting crosstalk in hardware equipment around the disk is generated, a write command or read command corresponding to the generated data pattern is executed, and the crosstalk is determined/detected based on the command execution result.

Abstract: A method and apparatus for enhancing performance of parity check in computer readable media is provided. For example, in a RAID (N+1) configuration, a virtual data strip is added for a calculation of parity. Data of the virtual data strip is set so that a predetermined portion of a data area in the virtual data strip has a predetermined value. Consequently, performance of parity check performed in a data processing system having a RAID configuration can be enhanced.

Abstract: A storage system has a plurality of disk storage devices and a controller for controlling the plurality of disk storage devices, and diagnosis of a write miss to a disk of the disk storage device. The controller for controlling the plurality of disk storage devices attaches an ID to write data, and after write access to the disk drive, the controller reads the write data from the disk drive, and compares the ID of the read data and the attached ID. The controller updates the ID for each write command. Therefore the old write data and the new write data can be identified, accurate diagnosis is possible, and the failure of an individual disk drive can be detected immediately.

Abstract: A RAID system access a physical disk and perform Rebuild/Copy back processing according to a host I/O request, so as to implement high-speed Rebuild/Copy back processing without interfering with the processing of a normal I/O. When one disk device fails, out of a plurality of disk devices constituting a RAID configuration, the controller performs Rebuild/Copy back processing to reconstruct the RAID. In Rebuild/Copy back, the controller reads the data from one disk and writes the data to another disk, so the presence of a normal I/O is judged, and when a normal I/O is absent, read and write of these different disk drives are executed simultaneously. By this, the Rebuild/Copy back time can be decreased.

Abstract: A RAID system access a physical disk according to a host I/O request, and perform Rebuild/Copy back processing, for implementing high-speed Rebuild/Copy back processing without interrupting the processing of a normal I/O. When one disk device out of a plurality of disk devices constituting the RAID configuration fails, the processing size for one time of Rebuild/Copy back to reconstruct the RAID is changed according to the presence of a normal I/O managed in RAID control. When a normal I/O is present, Rebuild/Copy back can be executed without interrupting the processing of the normal I/O, and in a static state where a normal I/O is absent, a processing size larger than the size in that state can be specified so as to implement Rebuild/Copy back processing at high-speed.

Abstract: A storage system has a control module for controlling a plurality of disk storage devices via a transmission path so as to discern the abnormalities of the plurality of disk devices and those of the transmission paths. When a control module for controlling the plurality of disk storage devices detects an error when the disk storage devices are accessed, the control module dummy-accesses the plurality of the disk storage devices on the transmission path, and specifies the suspected failure location based on the result. Therefore it can be discerned whether the suspected failure location is in the transmission path or the disk drive.

Abstract: A RAID control apparatus comprises at least a cache memory; an update information management table for storing update information; an update information storage unit for storing, in the update information management table, update information by detecting a data update; a reference value generation unit for generating a reference value expressing a load of a write back processing by using a Small Write method and a Read & Bandwidth Write method based on the update information; a write method determination unit for determining a write method according to the reference value and a write unit for carrying out a write processing, in order to provide a write back method for a RAID apparatus capable of improving a processing speed at the time of updating even in the case of including the processing of updating a part of data stripes.

Abstract: In a storage system, a disk device performs recovery and transfers read data to a control device, and the control device judges the validity of the recovery to prevent a transfer of erroneous data. A control device read-accesses a disk device, and the disk device returns read data and a recovered read error response. A control device, at the time of an initial recovered read error, performs a retry of a similar command, and if an error does not occur for read commands including the retry read command, judges the data to be valid. Uncertain data (suspect data) upon occurrence of a recovered read error is restored through disk retry, and accurate read data can be transferred to the host.

Abstract: A magnetic disk apparatus capable of effectively achieving speedup of the response to a read request, a control method and control program therefore are provided. In a control of a magnetic disk apparatus having a RAID configuration in which the same data is written on two disks, a given algorism is selected from a plurality of different algorisms with respect to the data stored in the disks, read commands are issued to the data stored in the two disks, respectively, according to the selected algorithm and the data that has been read first by the read commands that has been issued to the two disks in a read command issuance step is adopted as read data.

Abstract: The present invention has been made to obtain a magnetic disk apparatus and the like capable of using a patrol region in the magnetic disk to detect a location in need of maintenance in hardware equipment around the magnetic disk in a separate manner from the disk itself and thereby avoiding useless replacement and operating the magnetic disk apparatus at low cost. In a preventive maintenance detection for a magnetic disk apparatus having a patrol function that uses a patrol region in the magnetic disk to determine the presence/absence of the need of preventive maintenance, a data pattern for detecting crosstalk in hardware equipment around the disk is generated, a write command or read command corresponding to the generated data pattern is executed, and the crosstalk is determined/detected based on the command execution result.

Abstract: In a system for dispersively storing data and parity in a plurality of storage devices, information in a first storage device is restored by using information stored in the storage devices other than the first storage device when the first storage device fails. And information in a non-restored area in the first storage device and information in a second storage device are restored by using information stored in the storage devices other than the first and the second storage devices when the second storage device fails while the information in the first storage device is being restored.

Abstract: When a write-back request for writing back new data in a cache memory to disk devices forming a redundant configuration of RAID is generated, a write-back processing unit, reserves a parity buffer area in the cache memory, generates new parity, and then, writes the new data and the new parity to the corresponding disk devices. When an error in which the consistency of RAID is broken occurs in a plurality of the disk devices upon write performed by the write-back processing unit, a recovery processing unit reserves, in the cache memory, a cache stripe area storing data of the entire stripe including the new data which is to be written back, and causes the cache control unit to manage it.

Abstract: Storage destination controller devices wherein N number of data strips and M number of parity strips comprised in each stripe are determined so that the parity strips are not continuously stored to the same memory device between two consecutive stripes when a plurality of stripes, each comprising the N number of data strips and the M number of parity strips of different types, are distributed and stored to the N+M number of memory devices.