Hitachi, Ltd.

Hitachi Software Engineering Company, Ltd.

Hitachi Microcomputer System, Ltd.

Hitachi Microcomputer Engineering, Ltd.

Microcomputer Engineering Ltd.

Shigeo Honma

Akira Yamamoto

Hiroyuki Kitajima

Yoshihiro Asaka

Yoshiaki Kuwahara

Takao Satoh

Toshiaki Tsuboi

Michio Miyazaki

Koji Ozawa

Naoki Watanabe

Shizuo Yokohata

Youichi Gotoh

Takeshi Ido

Toshiyuki Yoshino

Manabu Kitamura

Hiroshi Arakawa

Hajime Sato

Takashi Oeda

Toshio Nakano

Takao Sato

Katsunori Nakamura

Masafumi Nozawa

Kiichiro Urabe

Akira Kurano

Hideo Ohata

Shigeru Kishiro

Ikuo Uratani

Tomohiro Murata

Yoshiro Shiroyanagi

Hiroshi Morishima

Kenzo Kurihara

Kosaku Kambayashi

Tokuhiro Tsukiyama

Masaharu Akatsu

Hiroyuki Matsushima

Yoji Tomono

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.

Load distribution of multiple disks

In response to requests for I/O processing sent from a computer, I/O which should be processed at a priority is enabled to be processed without being affected by other processing, by classifying I/O into those to be processed at a priority and those not to be processed at a priority. The storage control apparatus comprises an I/O processing controller with a memory that is common for the whole controller. The storage control apparatus manages information for dividing and controlling a plurality of I/O processes as priority and non-priority in that memory and operates while suppressing non-priority I/O processing on the basis of information in the memory.

Storage control apparatus

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.

Distribution of I/O requests across multiple disk units

In a disk array of the RAID constitution, a likelihood of occurrence of a failure is predicted from the number of times of error occurrence for each of disk drives #to #in a certain parity group. Two storage areas #_UH and #_LH of a half size, which are different in data stripes from each other, are selected from two disk drives #and #having a relatively high likelihood of occurrence of a failure, respectively, and the data thereof is copied to a spare disk #A (divided data copy). When the likelihood of occurrence of a failure of one disk drive #further increases, the remaining half storage area #OLH of the disk drive #is copied to the spare disk #A (dynamic sparing). Dynamic sparing time is reduced and a likelihood of data lost due to a multiple disk failure by employing the divided data copy processing.

Disk array device having spare disk drive and data sparing method

In order to construct an integrated storage system by reinforcing collaboration of components or functions of a storage system in which a storage area network (SAN) is used, in a computer system having multiple client computers, multiple various servers, multiple various storages which keep data, and a local area network (LAN) which connects the computers and the servers, a storage area network (SAN) which lies between the servers and storages forms a switched circuit network which is capable of connecting any server and any storage through fiber channel FC switches. The computer system further includes a terminal which is equipped with operation and management software which performs storage management including management of logical volumes in the various storages, data arrangement, error monitoring, management of setting up the FC switches, and backup for data in the storages.

Computer system having a storage area network and method of handling data in the computer system

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.

Storage system with data prefetch function

Disk storage system having capability for performing parallel read operation

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.

First host computer through a first interface sending to a second host computer a message including information about transfer data written to a storage subsystem through a second interface

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.

Storage subsystem having a plurality of interfaces conforming to a plurality of data formats

A sorting system includes a plurality of input nodes, each of which sorts sorting target data distributed and stored in input local disks. An internally sorted result is stored as a plurality of sorted strings in a shared disk connected between the input node and output node. Upon reception of a merge instruction from all input nodes, the output node reads the sorted string from the shared disk and merges it and outputs a whole sorted result of all input data to an output local disk. In a process of obtaining a whole sorted result of all input data through parallel processing by a computer system constituted of a plurality of computers (nodes), a time to sorting input data can be shortened.

Sorting system and method executed by plural computers for sorting and distributing data to selected output nodes

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.

Controller limiting modification of cache based upon amount of dirty

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.

Simultaneous read/write control of data storage disk units

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Tokyo, Japan

Shigeo Honma