Data processing system

Abstract

In a data processing system having a primary site and a secondary site, storage systems are connected to each other via a communication line, data update history is recorded in a storage device as a journal in the primary site, and the journal is transferred to the secondary site via the communication line. During such transfer, loads will not concentrate to a specific volume, by switching the volume that stores the journal in the primary site, while, by switching the transfer-destination volume of the journal in the secondary site. With such arrangement, in a data processing system, it is possible to ensure data consistency in a plurality of sites and prevent the system throughput capacity from being deteriorated without applying loads to a host and a network, and without causing load concentration on a specific storage device that is caused as a result of data update or recovery operations.

Description

BACKGROUND OF THE INVENTION [0001] The present invention refers to data processing systems, and more particularly to a data processing system that is suitable for use with a technology to distribute and store journals in a plurality of sites. [0002] The data processing system is demanded to prevent data loss in a storage system during disaster or the like. To this end, a technology to duplicate data in a storage system located in a remote place has a significant meaning. Note that the storage system referred to herein includes storage devices such as a storage controller and a disk drive. [0003] A technology to duplicate data stored in a storage system to another storage system is disclosed in U.S. Pat. No. 6,324,654. This patent further discloses a technology wherein, upon receipt of a write system call, a device driver of the OS of a computer (hereinafter referred to as a“primary host”) incorporated in a first system writes data to a local data device and stores update log in a wr...

AI Technical Summary

Benefits of technology

[0009] In the present invention, since recovery is performed by transferring a journal, not mere data, to the secondary site, it is possible to quickly recover data at no particular point of time upon occurrence of a failure, thus ensuring to guarantee data consistency.

[0010] Further, in the present invention, the primary storage system incorporates a plurality of logical volumes that store journals, and concentration of logical volumes and accesses in the journal transfer source can be avoided by switching storage logical volumes used at this time for journal logs, thus ensuring adequate load balancing.

[0011] Likewise, in the secondary storage system, concentration of accesses can be avoided by switching a logical volume of the journal transfer target that is used for journal transfer to set a volume different from the logical volume, thus ensuring adequate load balancing.

[0014] According to the present invention described above, there is provided a data processing system capable of recovering data by sampling data update logs. More specifically, the data processing system can assure data consistency on a plurality of sites, by giving no loads on the hosts and the network, and without causing deteriorated system processing capability, by avoiding centralized loads on a specific storage device to be caused as a result of data update or recovery.

Problems solved by technology

Since the data stored in the storage systems are transferred via a communication link between the hosts, the prior art had problems that the CPU loads of the respective hosts, channel loads, and traffics in a line connecting the hosts are increased.

Further, the prior art had another problem that, since no considerations are given on load balancing of the devices that occurs due to log sampling, log writing processes and log reading processes concentrate on the write log device.

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