The present invention relates to a copy processing technique for a data processing system having a plurality of disk array devices and particularly to an effective technique applicable to a process for simultaneously achieving long-distance communication and no data loss at a time of occurrence of disaster.
According to studies conducted by the inventors of the present invention, the following techniques are available to a conventional copy processing technique for the data processing system.
For example, in recent years, in order to always provide continuous services to a client, the data copying technique among a plurality of disk array devices have been suggested so that the services can be provided even when failure occurs in the disk array device such as a storage device for storing data. Particularly important is a technique for continuing and restarting data copying among remote sites and data copying at the time of failure. An example of a technique used in a data processing system having a plurality of disk array devices for copying, to second and third disk array devices, information stored in a first disk array device is disclosed in Patent Document 1 (U.S. Pat. No. 6,209,002).
In the Patent Document 1, a disk array device is provided to each of a local/production site, a first remote site, and a second remote site. Among these three disk array devices, the disk array device at the local/production site transfers data stored therein to the disk array device at the first remote site for copying. Then, the disk array device at the first remote site stores the transferred data and also transfers the data to the disk array device at the second remote site. Then, the disk array device at the second remote site stores the transferred data. Thereby, the technique for making the data redundant is disclosed.