摘要:
A disk conforms to a fixed length format and a storage subsystem shapes a CKD format record from a host computer in a fixed length unit to store shaped data therein. A format conversion program reads a fixed length block from the disk and extracts the shaped CKD format data to obtain such information to access a file system as file management information to thereby access the file system. Moreover, in an operation to write data on the disk, the data which the storage subsystem has received from the host computer is shaped in the conversion program into a sequence of data in a format to be written on the disk and then the sequence of data is written in a fixed length format thereon. Resultantly, data can be shared between systems using mutually different data formats to store data in storages.
摘要:
A first host computer writes data as an object of transfer and its location information to a storage subsystem. A second host computer reads out the data as an object of transfer which has been written to said storage subsystem on the basis of the location information thus written thereto. As a result, the data transfer between the host computers can be carried out employing the storage subsystem.
摘要:
In allocating an area of a cache memory to each storage unit, proper allocation of the cache memory is made to each storage unit. If the amount of write-after data becomes equal to or more than a threshold value, an allocation limit is set to each disk unit. If CPU issues a data write request requiring the amount of data equal to or more than the allocation limit, the data write request is held in a wait state until the amount of write-after data becomes less than the allocation limit. Therefore, the allocation amount to the disk unit becomes neither too large nor too small. In this manner, proper allocation of the cache memory to each disk unit can be realized.
摘要:
A method of respectively reading and writing data to and from a plurality of physical disk units in response to I/O requests from a host computing system includes establishing a logical disk group having a number of logical disk elements, mapping each of the logical disk elements to corresponding physical disk units, receiving from the host computing system an I/O request for data to select a one of the number of logical disk elements, accessing the physical disk unit corresponding to the selected one logical disk to access for the data, and transferring the accessed data to the host computing system.
摘要:
A method of respectively reading and writing data to and from a plurality of physical disk units in response to I/O requests from a host computing system includes establishing a logical disk group having a number of logical disk elements, mapping each of the logical disk elements to corresponding physical disk units, receiving from the host computing system an I/O request for data to select a one of the number of logical disk elements, accessing the physical disk unit corresponding to the selected one logical disk to access for the data, and transferring the accessed data to the host computing system.
摘要:
A disk storage system has a control unit having a plurality of external connection points. When the control unit receives two read requests issued from a processor to two disks of a disk unit group, a first read operation is performed to read data requested by the first read request from one of the disks and a second read operation is performed to read data requested by the second read request from the other one of the disks. Also, a first output operation is performed to output data read by the first read operation from one of the external connection points of the control unit and a second output operation is performed to output data read by the second read operation from another of the external connection points of the control unit. The second output operation is started before the first output operation has finished.
摘要:
The control unit arbitrarily selects a disk unit among the disk units that are inactive when the control unit receives an input/output request involving either read or staging. For a write request, the control unit selects a master disk unit in the disk unit group for the immediate writing of data, and a disk unit other than the above-mentioned master disk is preferably selected to execute the read and staging unit. After writing is used to write the data into the other disk units after the write request execution is completed by writing to the master disk unit.
摘要:
A storage system stores multiple copies of data on physical storage implemented, for example, with multiple disk units. Input/output read requests are received from host systems and distributed in a manner that allows parallel read operations to be conducted over the multiple disk units of the physical storage.
摘要:
The control unit arbitrarily with respect to the CPU, including according to an algorithm that is independent of the request a disk unit among the disk units that are inactive when the control unit receives an input/output request involving either read or staging. For a write request from the CPU, the control unit selects a specific disk unit in the disk unit group for the immediate writing of data. In the second kind of load distribution a disk unit is selected to execute read and staging other than the above-mentioned specific disk.
摘要:
A disk storage system has a control unit having a plurality of external ports connectable to a mirrored disk including two disks to which write data is written. When the control unit receives two read requests issued from a processor to the disk unit group, a first read operation is performed to read data requested by the first read request from one of the disks and a second read operation is performed to read data requested by the second read request from the other one of the disks. Also, a first transferring operation is performed to transfer data read by the first read operation to one external port of the control unit and a second transferring operation is performed to transfer data read by the second read operation to another external port of the control unit. Further, the data read by the two read operations is transferred to the processor via the external ports.