Abstract: A disk control apparatus includes a processor, and a memory coupled to the processor in which executes a process as follows. The process includes diagnosing whether or not a failure has occurred on each of a plurality of disk apparatuses, determining, when the failure has occurred, whether or not the failure is a pre-defined failure, and excluding from diagnosis targets, when the failure is the pre-defined failure, a disk apparatus group included in a RAID together with a failed disk apparatus that is determined to have the pre-defined failure in the plurality of disk apparatuses.

Abstract: A storage device includes: a determination unit to determine an operation of a storage group including a plurality of storage medium based on an access operation on a logical volume serving as an access target of the storage group; and a selection unit to select based on the operation of the storage group, when a failure of at least one of the plurality of storage medium is detected, an alternative storage medium from the at least one of the plurality of storage medium.

Abstract: A storage apparatus includes a plurality of first storage mediums in which data is redundantly stored and a controller. The controller includes a formatting section which performs formatting in each of the plurality of first storage mediums, a detection section which detects a failure that has occurred in the plurality of first storage mediums, a control section which makes the formatting section stop the formatting at the time of the detection of the failure by the detection section and which rebuilds the data stored in the plurality of first storage mediums in which the failure has occurred in a second storage medium other than the plurality of first storage mediums, and a rebuild processing section which rebuilds the data stored in the plurality of first storage mediums in the second storage medium in accordance with instructions from the control section.

Abstract: A control apparatus, coupled to a storage medium via communication links, controls data write operations to the storage medium. A cache memory is configured to store a temporary copy of first data written in the storage medium. A processor receives second data with which the first data in the storage medium is to be updated, and determines whether the received second data coincides with the first data, based on comparison data read out of the storage medium, when no copy of the first data is found in the cache memory. When the second data is determined to coincide with the first data, the processor determines not to write the second data into the storage medium.

Abstract: A control method includes the steps of storing data in a cache; generating parity data corresponding to the data stored in the cache and storing the parity data in a buffer; writing the data stored in the cache and the parity data stored in the buffer into a plurality of the storage units; reading the data and the parity data from the plurality of storage units; checking error over the read out data by using the read out parity data; storing, if an error is detected in the read out data and the read out parity data, data for reading a plurality of data constituting a stripe in each of the plurality of storage units in the buffer, regenerating parity data by using the plurality of data readout from the storage units; and overwriting the plurality of data and the parity data into the plurality of the storage units.

Abstract: According to an embodiment, a storage apparatus including: a plurality of storage media of which a first RAID is composed, a logical storage area of the first RAID for storing data being set over; a plurality of expansion storage media of which a second RAID is composed; a spare storage medium that is different from in any of the storage media or the expansion storage media; and a configuration control unit that when the spare storage medium is set in the first RAID, sets the logical storage area in the storage media, and when the expansion storage media are set in the storage apparatus, sets the expansion storage media in the second RAID, excludes the spare storage medium that is set in the first RAID, and moves the logical storage area that is set in the first RAID to the second RAID.

Abstract: A storage apparatus has a plurality of storage media including each storage area in which a stripe is set extending over the storage area of the plurality of storage media. An access unit that writes a format data into the storage area, wherein when the plurality of storage media are formatted, the access unit writes an unformatted-state identifier indicating incompletion of formatting into at least a portion of storage area to be included in the stripe, or when the storage area to be included in the stripe is accessed for writing new data, the access unit reads out existing data stored in the storage area included in the stripe to be accessed. And when the unformatted-state identifier is detected from the existing data that has been read out, the access unit writes the new data or the format data to be written by formatting into the storage area.

Abstract: According to an aspect of an embodiment, a method for controlling a controller connected to a plurality of storage units storing data, the controller including a cache and a buffer, the method comprising the steps of: storing data in the cache; generating parity data corresponding to the data and storing the parity data in the buffer; writing the data and the parity data into the plurality of the storage units; comparing the parity data stored in the buffer with the parity data written into and read out from at least one of the storage unit; deleting, when the parity data stored in the buffer is different from the parity data read out from the storage unit, the parity data from the buffer; and regenerating parity data from data stored in the cache and rewriting the regenerated parity data into at least one of the storage unit.

Abstract: According to an aspect of an embodiment, a method for controlling a controller connected to a plurality of storage units which are arranged in a redundant configuration, the controller reading data stored in the plurality of storage units in accordance with requests received from a host computer, the method comprising the steps of: receiving requests to read data successively from one of the storage units from the host computer; reading a part of requested target data from said one of the storage units; reading associated data and parity data stored in other storage units corresponding to other part of requested target data; generating other part of requested target data on the basis of the associated data and the parity data read out from the other storage units; and transmitting the part of the target data and the other part of the target data to the host computer.

Abstract: A disk management method for managing a disk management device for writing and reading data to and from a disk drive in which a recording medium is managed in a first control unit. The disk management method includes an error checking operation for checking an error on the recording medium in the first control unit, an error correction operation for correcting the error detected in the error, an error correcting operation for correcting the error detected in the error checking operation after converting data including the error to the second control unit, a data loss registration operation for registering a region in which data are lost due to an inconsistency between the first control unit and second control unit in a data loss region table, and a data loss recovery operation for recovering the loss of data with reference to the data loss region table.

Abstract: A storage unit includes a cache memory, a cache controller which accesses the cache memory, one or more disk units, a data receiving unit, a merge interpolation determination unit, a data readout unit, a write data generation unit and a data write unit. The data receiving unit receives, from the cache controller, unit readout data that includes update records updated by the cache controller and is unit of data read from the cache memory. The merge interpolation determination unit determines whether the received unit readout data is merge interpolated. The data readout unit reads, from the disk unit, data corresponding to the unit readout data when the unit readout data is determined to be merge interpolated. The write data generation unit generates data to be written to the disk unit by merge interpolating the unit readout data. The data write unit writes, to the disk unit, the generated data.

Abstract: A disk array apparatus includes a first converting unit that performs first conversion on storing object data received in a first control unit from a controller to convert the storing object data into data in a second control unit, the controller including a selecting section that selects, on the basis of the access state monitored by a monitoring section, one from the controller and said first converting unit, and a second converting unit that performs, if the controller is selected by the selecting section, a second conversion, different from the first conversion, on the object data to convert the object data managed in the first control unit into the data in the second control unit. With this configuration, the disk array apparatus accomplishes the object to improve the accessibility to different types of storage units that manage data storing in different control units.

Abstract: A control method includes the steps of storing data in a cache; generating parity data corresponding to the data stored in the cache and storing the parity data in a buffer; writing the data stored in the cache and the parity data stored in the buffer into a plurality of the storage units; reading the data and the parity data from the plurality of storage units; checking error over the read out data by using the read out parity data; storing, if an error is detected in the read out data and the read out parity data, data for reading a plurality of data constituting a stripe in each of the plurality of storage units in the buffer, regenerating parity data by using the plurality of data readout from the storage units; and overwriting the plurality of data and the parity data into the plurality of the storage units.

Abstract: According to an aspect of an embodiment, a method for controlling a controller connected to a plurality of storage units storing data, the controller including a cache and a buffer, the method comprising the steps of: storing data in the cache; generating parity data corresponding to the data and storing the parity data in the buffer; writing the data and the parity data into the plurality of the storage units; comparing the parity data stored in the buffer with the parity data written into and read out from at least one of the storage unit; deleting, when the parity data stored in the buffer is different from the parity data read out from the storage unit, the parity data from the buffer; and regenerating parity data from data stored in the cache and rewriting the regenerated parity data into at least one of the storage unit.

Abstract: According to an aspect of an embodiment, a method for controlling a controller connected to a plurality of storage units which are arranged in a redundant configuration, the controller reading data stored in the plurality of storage units in accordance with requests received from a host computer, the method comprising the steps of: receiving requests to read data successively from one of the storage units from the host computer; reading a part of requested target data from said one of the storage units; reading associated data and parity data stored in other storage units corresponding to other part of requested target data; generating other part of requested target data on the basis of the associated data and the parity data read out from the other storage units; and transmitting the part of the target data and the other part of the target data to the host computer.

Abstract: A disk management method for managing a disk management device for writing and reading data to and from a disk drive in which a recording medium is managed in a first control unit. The disk management method includes an error checking operation for checking an error on the recording medium in the first control unit, an error correction operation for correcting the error detected in the error, an error correcting operation for correcting the error detected in the error checking operation after converting data including the error to the second control unit, a data loss registration operation for registering a region in which data are lost due to an inconsistency between the first control unit and second control unit in a data loss region table, and a data loss recovery operation for recovering the loss of data with reference to the data loss region table.