Hitachi, Ltd.

Hitachi Microcomputer Engineering, Ltd.

Hitachi Microcomputer System, Ltd.

Hitachi Computer Engineering Co., Ltd.

Shigeru Kishiro

Akira Yamamoto

Katsunori Nakamura

Toshio Nakano

Yoshihiro Asaka

Yuichi Yagawa

Yoshinori Okami

Seiichi Higaki

Mikito Ogata

Hiroshi Abei

Misako Takahashi

Naoki Watanabe

Takashi Oeda

Yoshiro Shiroyanagi

Toshiaki Tsuboi

Takeo Fujimoto

Kenji Yamagami

Takao Sato

Kouji Arai

Hiroyuki Kitajima

Akira Kurano

Kyosuke Achiwa

Shigeo Honma

Haruaki Watanabe

Takeshi Koide

Takahiko Takeda

Naohisa Kasako

Keiichi Kaiya

Michio Miyazaki

Yoshiaki Kuwahara

Teruo Nagasawa

Takahisa Kimura

Yoshiaki Muto

Tomohito Ogino

A method for copying data to multiple remote sites includes transmitting data from a first volume in a primary storage system to a back-up volume provided in a secondary storage system. The primary storage system is located at a primary site, and the secondary storage system is located at a first remote site from the primary site. The data from the first volume in the primary storage system is copied to a second volume in the primary storage system using a point in time (PiT) as a reference point of time for the copying. The second volume is provided with a first time consistent image of the first volume with respect to the reference point of time. The data from the second volume in the primary storage system is transferred to a third volume in a ternary storage system at a second remote site. The third volume is provided with a second time consistent image of the second volume with respect to the reference point of time, where the second time consistent image is a mirror image of the first time consistent image. The data from the third volume is transferred to a fourth volume in the ternary storage system. The fourth volume is provided with a third time consistent image. In the ternary storage, either of the third volume or fourth volume can always keep time consistent image of the first volume.

Point in time remote copy for multiple sites

A primary controller operates to transmit write data and a write time to a secondary controller in the earlier sequence of the write times after reporting a completion of a request for write to a processing unit. The secondary controller stores the write data and the write time transmitted from the primary controller in the cache memory. At a time, the secondary controller stores the write data in a disk unit in the earlier sequence of the write time. These operations make it possible to guarantee all the write data on or before the reference time.

Storage controller

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 with reduced data size

Remote copy for a storage controller in a heterogeneous environment

A storage apparatus configuration in a three data center architecture comprises first and second data storage systems, and a remote data storage system. The first data storage systems can copy an image of data stored therein to the remote data storage system without affecting access to storage in the first data storage system. The second data storage system is configured to perform a takeover operation if the first data storage system becomes unavailable.

Three data center adaptive remote copy

A method is provided for improving the performance of copy operations in storage systems. The method includes storing a measure of relative availability of storage system resources, detecting operations when sequential portions of a storage media are to be accessed for writing of information, and when the measure of relative availability of system resources drops to a specified extent, introducing a wait into the operation in which sequential portions of a storage media are to be accessed for writing of information. In another implementation, a method is provided for controlling writing of data in a storage system in which a step is performed of analyzing a requested write operation to determine if the requested write operation calls for a sequential task or a random task. If the requested write operation is a sequential task, information about it is stored in a task management table. the table is used to determine if throttling is needed to carry out the requested write operation, and invokes throttling if it is needed.

Throttling in storage systems

A technique is described to enable exclusive control on a file basis in a storage system while remote double recording is performed between storage controllers. A first shared-file controller has a table that stores control information used for excluding read and write to that file on a file basis. When the shared-file controller receives a data write request, it sets access to the file as exclusive, and then issues a command to a second shared file controller to set control information for that file. After data is written into a storage medium and mirrored to a second storage medium, a copy of the file management information is stored in memories of the shared-file controllers. The consistency of the file management information is maintained between the two file controllers by copying the file management information over the network.

Method, apparatus and system for remote file sharing

A storage subsystem in which write data written in a first storage subsystem from a plurality of host computers is copied onto a second storage subsystem, thereby protecting the write data in a multiplex manner. Disclosed are a storage subsystem and its controlling method in which the first storage subsystem has a storage control unit which sets a first threshold for controlling for each of the host computers an occupancy ratio of the write data whose copy to the second storage subsystem is incomplete in a data buffer in the first storage subsystem, and has control logic for delaying the processing of a data write request from each of the host computers on the basis of the first threshold.

Storage subsystem and its controlling method

A storage system and method are provided and feature a highly available remote copying function and site switching capability. A redundant constitution to a sequencing generator for producing sequence information is provided. In a remote copy configuration, a sequence generator is provided at the copy destination site, in addition to the copy source site. The sequence generators are configured for redundant operation for site switching.

Remote mirroring with write ordering sequence generators

Growing community of inventors

Odawara, Japan

Shigeru Kishiro