Abstract: A storage apparatus includes a plurality of nodes, each of the plurality of nodes including a memory configured to store distributed data distributed and allocated to each of the plurality of nodes, and a processor coupled to the memory and configured to secure an empty storage region different from a storage region storing the distributed data on the memory when a new node is added to the plurality of nodes and move the distributed data to the empty storage region secured in the plurality of nodes and the new node.

Abstract: A storage control apparatus obtains first-code attached data, each having target data to be written and first code information, which includes an error detection code based on the target data and information about a first write destination, attached to the target data. The storage control apparatus then obtains the target data by excluding the first code information from the first-code attached data eliminates duplication of the target data, generates second code information which includes an error detection code for the target data remaining and information about a second write destination, and writes second-code attached data including the second code information into a memory device.

Abstract: There is provided a storage control apparatus that obtains first-code attached data, each having target data to be written and first code information, which includes an error detection code based on the target data and information about a first write destination, attached to the target data; obtaining the target data by excluding the first code information from the first-code attached data; eliminating duplication of the target data; generating second code information which includes an error detection code for the target data remaining and information about a second write destination; and writing second-code attached data including the second code information into a memory device.

Abstract: A storage apparatus includes a copy control unit for managing a copy session for copying an copy source data area in at least one of the first to the Mth copy source disk groups to an copy destination data area in a corresponding copy destination disk group, setting a first to an Mth copy session groups, each of the copy session groups including one or more copy sessions from the ith copy source disk group to the ith copy destination disk group as the copy session, and performing repeatedly a selection operation for cyclically selecting a copy session from each of the first to the Mth copy session groups in a predetermined sequence and a control operation for cyclically executing copy processing on a predetermined copy processing unit basis for the M copy sessions selected by the selection operation in a predetermined sequence for a prescribed number of times.

Abstract: A RAID control apparatus and control method. The RAID control apparatus includes disk devices and disk control devices including a cache memory that stores cache data of a logical unit, and control unit, upon the logical units present in different disk devices being concatenated to each other, switching in-charge disk control devices such that a disk control device is in charge of access to the concatenated logical units without writing back the cache data stored in a cache memory of a source disk control device to the disk device.

Abstract: A cache managing unit creates a list of elements corresponding to each data block arranged based on a priority of writing data blocks to a magnetic disk apparatus, and when a group of elements corresponding to data blocks to be written to the same magnetic disk apparatus exists, provides a link connecting elements at both ends of the group. A write control unit searches, upon selecting a data block for writing, elements belonging to the list in descending order of priority, and if a link is set at an element corresponding to a data block to be written to a magnetic disk that cannot perform a writing, follows the link to search a subsequent element.

Abstract: A storage apparatus includes a copy control unit for managing a copy session for copying an copy source data area in at least one of the first to the Mth copy source disk groups to an copy destination data area in a corresponding copy destination disk group, setting a first to an Mth copy session groups, each of the copy session groups including one or more copy sessions from the ith copy source disk group to the ith copy destination disk group as the copy session, and performing repeatedly a selection operation for cyclically selecting a copy session from each of the first to the Mth copy session groups in a predetermined sequence and a control operation for cyclically executing copy processing on a predetermined copy processing unit basis for the M copy sessions selected by the selection operation in a predetermined sequence for a prescribed number of times.

Abstract: A system creates a configuration definition table to be used for accessing a physical disk according to a host I/O request, to decrease a memory size of the configuration definition table even if common firmware is used for models with different scales. For this, a model correspondence table to show the definition of each model is provided in a configuration setup processing module, the maximum values of this model are recorded in a memory based on this content, and a memory area for each item is secured. And the actual content of the configuration definition is developed on the secured memory. Therefore even for a diversity of models, the memory size of the configuration definition table can be decreased to a size matching the model, with common firmware regardless the model.

Abstract: An interdevice communication monitoring unit 62-1 calculates a variable timeout time (T2?T) by subtracting an elapsed time T from a predetermined fixed timeout time T2 for monitoring an intermodule communication to monitor an elapsed time of an intermodule communication. The fixed timeout time T2 is a time shorter than a predetermined interface connection check time T1 for monitoring an interface connection with a channel. When the elapsed time T of the intermodule communication exceeds the variable timeout time (T2?T), the interdevice communication monitoring unit requests a channel to separate the interface connection, and then when an end response is obtained from a control module, requests the channel for an interface reconnection and then transmits an end response.

Abstract: In the present invention, for each set of blocks [#(0) to #(N?1)] storing update data, a history block [#(N)] storing an update state value, for example, a generation, time or check code, showing an update state is provided, constituting a set of management data as a check object. When writing update data on a disk, a new update state value is calculated for the same set of management data and stored in memory as update state confirmation value. The new update state value is also set as write data in the history block in the same set of management data, and the entire of the set of management data including update data and update state value are written onto a disk. The history block is read and disk write omissions are detected by comparing the update state value and the update state confirmation value stored in memory.

Abstract: A RAID control apparatus and control method. The RAID control apparatus includes disk devices and disk control devices including a cache memory that stores cache data of a logical unit, and control unit, upon the logical units present in different disk devices being concatenated to each other, switching in-charge disk control devices such that a disk control device is in charge of access to the concatenated logical units without writing back the cache data stored in a cache memory of a source disk control device to the disk device.

Abstract: A cache managing unit creates a list of elements corresponding to each data block arranged based on a priority of writing data blocks to a magnetic disk apparatus, and when a group of elements corresponding to data blocks to be written to the same magnetic disk apparatus exists, provides a link connecting elements at both ends of the group. A write control unit searches, upon selecting a data block for writing, elements belonging to the list in descending order of priority, and if a link is set at an element corresponding to a data block to be written to a magnetic disk that cannot perform a writing, follows the link to search a subsequent element.

Abstract: In order to provide a disk cache control apparatus allowing an upper level apparatus to carry out a high speed access even if the upper level apparatus accesses a discretionary area of a logical volume, the disk cache control apparatus comprises at least a data storage unit for storing data read out of a lower level apparatus temporarily or for a predefined time, a management information storage unit for storing management information which correlates an area of a logical volume with that of the data storage unit, a management information generation unit for generating the management information, and an access processing unit for accessing data of either the data storage unit or a lower level apparatus.

Abstract: An interdevice communication monitoring unit 62-1 calculates a variable timeout time (T2?T) by subtracting an elapsed time T from a predetermined fixed timeout time T2 for monitoring an intermodule communication to monitor an elapsed time of an intermodule communication. The fixed timeout time T2 is a time shorter than a predetermined interface connection check time T1 for monitoring an interface connection with a channel. When the elapsed time T of the intermodule communication exceeds the variable timeout time (T2?T), the interdevice communication monitoring unit requests a channel to separate the interface connection, and then when an end response is obtained from a control module, requests the channel for an interface reconnection and then transmits an end response.

Abstract: A storage system prevents a time out error of the host I/O caused by a stagnation of command processing in the storage system for accessing a disk device according to the host I/O request and internal I/O request. In DTC, counters for managing the requests in-process for host I/Os (host read) and internal I/Os (pre-fetch, write back) individually are provided, and the number of processing requests to be issued to a virtual disk (RLU) is limited individually. By assigning priority to the host I/Os, the load balance of the host I/Os and internal I/Os can be controlled. For rebuild/copy back, a dedicated load control mechanism is disposed where the load adjustment between ordinary I/Os and rebuild/copy back is performed.

Abstract: A system creates a configuration definition table to be used for accessing a physical disk according to a host I/O request, to decrease a memory size of the configuration definition table even if common firmware is used for models with different scales. For this, a model correspondence table to show the definition of each model is provided in a configuration setup processing module, the maximum values of this model are recorded in a memory based on this content, and a memory area for each item is secured. And the actual content of the configuration definition is developed on the secured memory. Therefore even for a diversity of models, the memory size of the configuration definition table can be decreased to a size matching the model, with common firmware regardless the model.

Abstract: In the present invention, for each set of blocks [#(0) to #(N?1)] storing update data, a history block [#(N)] storing an update state value, for example, a generation, time or check code, showing an update state is provided, constituting a set of management data as a check object. When writing update data on a disk, a new update state value is calculated for the same set of management data and stored in memory as update state confirmation value. The new update state value is also set as write data in the history block in the same set of management data, and the entire of the set of management data including update data and update state value are written onto a disk. The history block is read and disk write omissions are detected by comparing the update state value and the update state confirmation value stored in memory.

Abstract: In the present invention, for each set of blocks [#(0) to #(N-1)] storing update data, a history block [#(N)] storing an update state value, for example, a generation, time or check code, showing an update state is provided, constituting a set of management data as a check object. When writing update data on a disk, a new update state value is calculated for the same set of management data and stored in memory as update state confirmation value. The new update state value is also set as write data in the history block in the same set of management data, and the entire of the set of management data including update data and update state value are written onto a disk. The history block is read and disk write omissions are detected by comparing the update state value and the update state confirmation value stored in memory.

Abstract: A primary disk and a secondary disk that duplicates the data in the primary disk are connected to a host computer via a disk-array control unit. The disk-array control unit includes a plurality of central management units. Each central management unit includes a cache memory for writing data accessed, and a command-process executing unit that executes a process based on a command received. Each central management unit executes a process including determining, when there is an error in data stored in the primary disk while data stored in the secondary disk is normal, that a recovery process is necessary, duplicating, after completing an input/output process with the host computer, data written in the cache memory into a cache memory of any other central management unit, and writing-back the data written in the cache memory into the primary disk and the secondary disk.

Abstract: The present invention has been developed to carry out the dual-writing of data in cache memories at a higher speed through a single address designation for the improvement of processing performance. In the present invention, a host interface module produces addressing information for designating two written-in destinations, and a bridge module produces two transferred-to addresses and written-in addresses of the cache memories on the basis of the addressing information so that data to be written is transferred to two management modules corresponding to the two transferred-to addresses to be written at the written-in addresses of the cache memories of the management modules.