Computer-readable recording medium containing database copying program, and database copying apparatus and method

Abstract

A computer-readable recording medium containing a database copying program for making a copy of a database on a remote computer being connected over a network, without causing a delay in replying to an application program. A mirroring unit copies data written on a plurality of local disks onto corresponding remote disks in the same sequence as the data was written. Upon reception of a data writing request, a data writing unit stores the data in a local disk selected as a current disk. When the data stored in the current disk reaches a maximum data capacity, the current disk manager switches the current disk to another local disk. In addition, when the data stored in the current disk reaches the maximum data capacity, an operation information manager stores operation information requesting backup of the data stored in the current disk, in a local disk selected as an operation information storage disk.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a principle view showing the invention that is implemented in one embodiment.

FIG. 2 shows a system configuration of the embodiment.

FIG. 3 shows a hardware configuration of a host computer.

FIG. 4 is a functional block diagram of the host computer.

FIG. 5 is a functional block diagram of a remote computer.

FIG. 6 shows an example data structure of an operation information table.

FIG. 7 is a flowchart showing how to update host data.

FIG. 8 is a flowchart showing how to update remote data.

FIG. 9 shows an example of a mirroring process between disks.

Claims

1. A computer-readable recording medium containing a database copying program for making a copy of a database on a remote computer being connected over a network, causing a computer to perform as: mirroring unit for, when data is written on a plurality of local disks individually, writing duplicate data of the data on remote disks in a same sequence as the data was written, the remote disks provided in the remote computer to correspond to the plurality of local disks, respectively;current disk management means for selecting one local disk out of the plurality of local disks as a current disk, and when stored data of the current disk reaches a preset maximum data capacity, switching the current disk to another local disk;data writing means for, when a data writing request arrives, writing the data on the current disk; andoperation information management means for selecting some other local disk out of the plurality of local disks as an operation information storage disk, and when the stored data of the current disk reaches the preset maximum data capacity, storing first operation information requesting backup of the duplicate data of the data stored in the current disk, in the operation information storage disk.

2. The computer-readable recording medium according to claim 1, wherein the database copying program further causes the computer to perform as database update means for, when an update request specifying a way for updating the database arrives, executing an update process of the database according to the update request arriving, and outputting to the data writing means the data writing request of an update log for the update process executed.

3. The computer-readable recording medium according to claim 1, wherein the database copying program further causes the computer to perform as operation information reception means for, when receiving second operation information indicating completion of the backup of the duplicate data of the data stored in the one local disk, issuing to the current disk management means a notification indicating that the one local disk specified by the second operation information received becomes selectable as the current disk, wherein the current disk management means specifies the one local disk selected as the current disk before switching of the current disk, as an unselectable local disk for the current disk at the time of the switching, and when receiving the notification from the operation information reception means, cancels the specification of the one local disk specified by the notification received.

4. A database copying apparatus for making a copy of a database on a remote computer being connected over a network, the database copying apparatus comprising: mirroring unit for, when data is written on a plurality of local disks individually, writing duplicate data of the data on remote disks in a same sequence as the data was written, the remote disks provided in the remote computer to correspond to the plurality of local disks, respectively;current disk management means for selecting one local disk out of the plurality of local disks as a current disk, and when stored data of the current disk reaches a preset maximum data capacity, switching the current disk to another local disk;data writing means for, when a data writing request arrives, writing the data on the current disk; andoperation information management means for selecting some other local disk out of the plurality of local disks as an operation information storage disk, and when the stored data of the current disk reaches the preset maximum data capacity, storing operation information requesting backup of the duplicate data of the data stored in the current disk, in the operation information storage disk.

5. A database copying method having mirroring means for, when data is written on a plurality of local disks individually, writing duplicate data of the data on remote disks in a same sequence as the data was written, the remote disks provided in a remote computer to correspond to the plurality of local disks, respectively, wherein: data writing means, when receiving a data writing request, writes the data on one local disk selected as a current disk out of the plurality of local disks;current disk management means, when stored data of the current disk having the data written thereon reaches a preset maximum data capacity, switches the current disk to another local disk; andoperation information management means, when the stored data of the current disk having the data written thereon reaches the preset maximum data capacity, stores operation information in some other local disk selected as an operation information storage disk out of the plurality of local disks, the operation information requesting backup of the duplicate data of the data stored in the current disk.