Hitachi, Ltd.

Other

Hitachi Information Technology Co., Ltd.

Teruo Nagasawa

Takeshi Koide

Katsunori Nakamura

Takahisa Kimura

Tooru Suzuki

Takao Satoh

Takashi Oeda

Toshio Nakano

Yoshihiro Asaka

Yoshinori Okami

Seiichi Higaki

Kyosuke Achiwa

Shigeru Kishiro

Mikito Ogata

Hiroshi Abei

Kosaku Kambayashi

Yasushi Saitsu

Kosaku Kamabayashi

Two data centers located in the vicinity are connected using a synchronous transfer copy function, and one of the data centers is coupled with a third data center disposed at a remote location by an asynchronous remote copying function. The order whereat a storage sub-system located in the vicinity has received data from a host is consistently guaranteed, and the third data center holds the data. Further, each storage sub-system includes a function whereby, during normal operation, data can be exchanged and the data update state can be obtained by the storage sub-systems located in the two data centers that do not directly engage in data transmission.

Remote copy for a storage controller in a heterogeneous environment

A storage system which includes a first storage device, and a storage control device connected to a higher level device and the first storage device. The storage control device controls reading or writing of data from or to the higher level device to or from the storage control device. The storage control device can be connected to another storage control device, and can acquire device information of the other storage control device.

Subsystem replacement method

A storage apparatus system comprises first and second data storage systems. The first data storage systems can copy an image of data stored therein to the second data storage system without affecting access to storage in the first data storage system. In addition, failover processing is provided between the first and second data storage systems, wherein the second data storage system serves as the failover system.

Adaptive remote copy in a heterogeneous environment

With the purpose of achieving consistent non-synchronous copying of data from a plurality of primary side control units to a plurality of secondary side control units, all of the secondary side control units are connected via a loop, and each of the secondary side control units determines guarantee time by circulating a time added to the data received from the primary side control units via said loop communication route. A consistent data copying is guaranteed by circulating the determined guarantee time via the loop communication route.

Method and apparatus for data duplexing in storage unit system

A storage system which includes a first storage device, and a storage control device connected to a higher level device and the first storage device. The storage control device controls reading or writing of data from or to the higher level device to or from the storage control devices. The storage control device can be connected to another storage control device, and can acquire device information of the other storage control device.

According to the present invention, techniques for performing real time backup of data in the presence of a pending hazard, such as a natural disaster, or the like. Embodiments can provide data storage controllers, networked data storage systems, methods and the like, that detect imminent hazardous conditions and alter backup behavior to provide greater integrity of backed up data. In a representative embodiment according to the present invention, update of the primary data is temporarily suspended after the recognition of a probable occurrence of a hazardous event. By suspending updating the primary data temporarily, the increase of un-updated secondary data can be prevented, so that lost data is decreased. Then, the un-updated secondary data can be updated quickly or exclusively, in order to avoid un-updated secondary data.

Data backup in presence of pending hazard

According to the present invention, techniques for performing real time backup of data in the presence of a pending hazard, such as a natural disaster, or the like are disclosed. Embodiments of the invention provide data storage controllers, networked data storage systems, methods and the like, that detect imminent hazardous conditions and alter backup behavior to provide greater integrity of backed up data. In a representative embodiment according to the present invention, update of the primary data is temporarily suspended after the recognition of a probable occurrence of a hazardous event. By suspending updating the primary data temporarily, the increase of un-updated secondary data can be prevented, so that lost data is decreased. Then, the un-updated secondary data can be updated quickly or exclusively, in order to avoid un-updated secondary data.

In order to enable data migration between old and new subsystems to be performed under stopless operation, a plurality of first access paths and are prepared between a CPU and an old CU (old subsystem) having an old VOL and a plurality of third access paths and are set between the old CU and a new CU (new subsystem) having a new VOL. The connection is switched from the first access paths and of the old subsystem as a replacement source to the second access paths and of the new subsystem as a replacement destination on a plurality of occasions. When the CPU accesses the new subsystem via the second access paths and on the new subsystem side during the connection change, a path replacement controller relays the access to the old subsystem via the third access paths and and allows the access to be processed. Data migration from the old subsystem to the new subsystem is executed after all of the first access paths are switched to the second access paths.

By assuring and maintaining consistency of data within a range expected by the user, significance of the consistency of data is assured. A master control unit to which write data and its write time is transferred from an information processor is provided with a function of obtaining the latest write time and the oldest write time of write data which has not been copied to each of remote control units as a copy destination at proper timings and comparing the difference between the latest and oldest write time with a preset time on the basis of a data consistency unit such as a data set. When the difference reaches or exceeds the present time, data within the data consistency assuring range is suspended or write data and copy data is regulated.

Information storage system

In order to enable data migration between old and new subsystems to be performed under stopless operation, a plurality of first access paths are prepared between a CPU and an old CU (old subsystem) having an old VOL and a plurality of third access paths are set between the old CU and a new CU (new subsystem) having a new VOL. The connection is switched from the first access paths of the old subsystem as a replacement source to the second access paths of the new subsystem as a replacement destination on a plurality of occasions. When the CPU accesses the new subsystem via the second access paths on the new subsystem side during the connection change, a path replacement controller relays the access to the old subsystem via the third access paths and allows the access to be processed. Data migration from the old subsystem to the new subsystem is executed after all of the first access paths are switched to the second access paths.

A disk cache control unit disposed between an upper-rank processor and a disk unit, comprising a cache memory for holding a copy of data stored in the disk unit, at least one first interface controller which checks, in response to an input/output command requesting data to be read from the upper-rank processor, whether or not the data requested by the command is stored in the cache memory, and requests a head positioning of the disk unit when the data is not stored in the cache memory, and a second interface controller which indicates head positioning to the disk unit in response to a head positioning request, notifies the completion of the head positioning to the first interface controller in response to a notice of the completion of the head positioning, and which reads data from the disk unit and stores the data in the cache memory when a data transfer request did not come in a specified time period set to read data from the disk unit without a rotational delay after a notice of the head positioning head been given to the first interface controller and the subsequent transfer of data from the second interface controller had been completed, and which gives a notice of storage of the data in the cache memory through memory means to the first interface controller, and in response to this storage notice, the first interface controller reads the data from the cache memory and transfers the data to the upper-rank processor.

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Odawara, Japan

Teruo Nagasawa