JP2001175518A - System and method for preparing backup, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly back up a data file within a prescribed time in optimal state all the time and further regardless of the kind of backup medium or the like without trouble in access to the backup object file during backup. SOLUTION: A backup information preparing part 5 receives a backup request from a console 10 and a write controller part 2 inhibits write to a data file 3 and changes the write destination of a write request to the data file 3 applied from a data input/output part 1 to a virtual file 4. The backup information preparing part 5 prepares a backup information file 6 of the data file 3 and on the basis of that file, a backup controller part 7 reads out the data file 3 and writes it to a backup file 8. When backup is completed, write inhibition is canceled and the file written in the virtual file 4 is moved to the data file 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for creating a backup copy of a data file such as a database, and more particularly to a backup creation system, method and recording that appropriately considers access to a backup target data file during backup. Regarding the medium.

[0002]

2. Description of the Related Art A conventional backup creation system executes backup software installed on an external device 101 as shown in FIG.
Create a backup copy of data file 102. That is, by executing the backup software, the configuration file information of the backup target data file 102, that is, the backup target data file 10
A backup information file 104 composed of information on the files constituting the backup information file 2 is created, and files on the backup target data file 4 are stored in the backup file 103 according to the backup information file 104.

That is, the backup creation system shown in FIG. 6 operates according to the flowchart shown in FIG. When the backup software is started on the external device 101, first, the backup target data file 102 is read, a backup information file 104 is created (step S101), and the backup target data file 102 is created according to the backup information file 104.
Files are sequentially read. At the time of reading the backup target data file 102, it is determined whether or not the file is being written (step S102). If the file is being written, the file information being written is accumulated, and the next file information is stored. The file is read (step S103). If the file is not being written, the read file is written to the backup file 103 (step S104).

As described above, the files that are being written at the time of backup are postponed, and the files that constitute the data file to be backed up are sequentially backed up. Therefore, depending on the timing of the write processing, the backup operation may not be completed forever. There is.

After the backup information file 104 is created, the backup target data file 102
When the files that make up the file are updated, inconsistency occurs in the writing time of the file, so that a factor that delays the completion of the backup often occurs, such as reconstructing the backup information file. Therefore, it is difficult to perform stable backup. Therefore, stable backup operation is required.

As described above, an example of the prior art for monitoring the update history during backup is disclosed in Japanese Patent Application Laid-Open No. 5-143425. Japanese Patent Application Laid-Open No. Hei 4-235645 discloses that when data to be backed up is accessed during a backup operation, the data to be backed up is saved, and the saved data is used for backup to update the data to be backed up. It has been disclosed. And, JP
Japanese Patent Application Laid-Open No. 1-120057 discloses a control method at the time of backup in parallel input / output control for files distributed and arranged on a plurality of disk devices. In Japanese Patent Application Laid-Open No. H11-120057, update information is managed at the time of backup, and only the updated portion of the contents already backed up is provided for backup.
It is disclosed that a target file is locked during backup, and if there is an update request during backup, update information is stored in another area and reflected after backup.

[0007]

As described above, in the conventional backup creation system, measures for accessing a backup target data file during backup are not always sufficient. In other words, it is not always appropriate to determine in what state the access during backup is performed for the backup target data file, and when the access during backup is permitted, at what timing the state of the backup target data file is backed up. Did not. In addition, access during backup and its post-processing significantly increase the time required for backup.
The time required for backup was significantly affected by the access situation during backup.

The present invention has been made in view of the above-mentioned circumstances, and does not hinder access to a data file to be backed up during a backup. Regardless, it is an object of the present invention to provide a backup creation system, method, and recording medium that can smoothly perform backup in a predetermined time.

[0009]

In order to achieve the above object, a backup creation system according to a first aspect of the present invention controls writing of a data file to be backed up, and writes the data file to be backed up during a backup operation. In response to a write request to the data file to be backed up, a write to a virtual file different from the data file to be backed up is performed. Write control means for releasing write protection to the virtual file and transferring the file written to the virtual file to the data file to be backed up, and during the backup operation, the write control means prohibits writing to the data file to be backed up Doing In the meantime, backup information creation means for reading file information of the backup target data file and creating a backup information file, and a file from the backup target data file based on the information of the backup information file created by the backup information creation means And writing the data to a backup file and, when writing is completed, a backup control means for notifying the write control means of the completion of the backup.

In the backup creation system of the present invention, writing of the data file to be backed up is controlled by the write control means, and during the backup operation, writing to the data file to be backed up is prohibited, and writing to the data file to be backed up is prohibited. In response to the write request, write to a virtual file different from the backup target data file, and when the completion of the backup is notified, release the write-protection to the backup target data file and write to the virtual file. The backup file is transferred to the backup target data file. At the time of the backup operation, while the write control unit prohibits writing to the backup target data file, the backup information creation unit reads the file information of the backup target data file and creates a backup information file. Further, based on the information of the backup information file created by the backup information creating means, the backup control means reads a file from the backup target data file, writes the file in the backup file, and when the writing is completed, the write control means Notify backup completion. Therefore, even during the backup, the data file to be backed up can be accessed without any trouble, and the data file to be backed up can be smoothly backed up in a predetermined time irrespective of the type of the backup medium, always in an optimum state. .

In response to a read request from the backup target data file at the time of the backup operation, the write control means reads from the virtual file when the target file exists in the virtual file. May include means for reading from the backup target data file when the target file does not exist.

When a write request to the backup target data file is issued after the completion of the backup, the write control means gives the file information to the backup information creating means, and after the write based on the write request is completed, the backup control means Means for performing an operation, and the backup information creating means, when receiving file information requested to be written from the write control means, adding the file information to the backup information file via the backup information creating means May be included.

A backup creation method according to a second aspect of the present invention, in response to a backup request, prohibits writing to a backup target data file, and responds to a write request to the backup target data file. A first write control step for writing to a virtual file different from the backup target data file; and a step in which writing to the backup target data file is prohibited by the first write control step. A backup information creation step of reading file information of the backup target data file and creating a backup information file; and a backup information file based on the information of the backup information file created by the backup information creation step. A file is read from the backup control step to write to the backup file, and when the writing of the backup target data file to the backup file by the backup control step is completed, the write-protection to the backup target data file is released, And a second write control step of transferring information written to the virtual file while the writing to the backup target data file is prohibited, to the backup target data file.

In the backup creation method according to the present invention, writing to the backup target data file is prohibited in response to the backup request, and the backup target data file is responded to in response to the write request to the backup target data file. In this case, writing to a virtual file different from the above is performed. While the writing to the backup target data file is prohibited, the file information of the backup target data file is read, and a backup information file is created. Based on the information in the backup information file, a file is read from the data file to be backed up and written to the backup file. Then, when the writing from the backup target data file to the backup file is completed, the write prohibition on the backup target data file is released, and the data is written to the virtual file while the write prohibition on the backup target data file is prohibited. The information is transferred to the backup target data file. Therefore, even during the backup, the data file to be backed up can be accessed without any trouble, and the data file to be backed up can be smoothly backed up in a predetermined time irrespective of the type of the backup medium, always in an optimum state. .

In response to a read request from the data file to be backed up during the backup operation, if the target file exists in the virtual file, reading is performed from the virtual file, and the target file does not exist in the virtual file. In this case, the method may further include the step of reading from the backup target data file.

When a write request to the data file to be backed up occurs after the completion of the backup,
Adding the file information to the backup information file, prohibiting writing to the backup target data file after completion of the writing based on the writing request, and, for the writing request to the backup target data file, The step of causing a write to a virtual file different from the backup target data file, and, based on the information of the backup information file to which file information is added, read a file from the backup target data file,
Writing to the backup file, and upon completion of writing from the backup target data file to the backup file, canceling the write-protection to the backup-target data file and releasing the virtual Transferring the information written in the file to the backup target data file.

According to a third aspect of the present invention, there is provided a computer-readable recording medium which controls a computer to write a data file to be backed up, and prohibits writing to the data file to be backed up during a backup operation. In response to a write request to the backup target data file, write to a virtual file different from the backup target data file, and when backup completion is notified, release the write prohibition to the backup target data file. hand,
Write control means for transferring a file written to the virtual file to the backup target data file, and during the backup operation, the backup target data file while the write control means prohibits writing to the backup target data file. The file information is read from the backup target data file based on the information of the backup information file created by the backup information creating means for creating the backup information file and the backup information file created by the backup information creating means. At the time of writing, a program for functioning as a backup control means for notifying the write control means of the completion of the backup upon completion of the writing is recorded.

According to a fourth aspect of the present invention, there is provided a computer-readable recording medium which controls a computer to write a data file to be backed up, and prohibits writing to the data file to be backed up during a backup operation. In response to a write request to the backup target data file, write to a virtual file different from the backup target data file,
And, in response to a read request from the backup target data file at the time of the backup operation, when there is a target file in the virtual file, reading is performed from the virtual file, and when there is no target file in the virtual file, Performs reading from the data file to be backed up, and when the completion of the backup is notified, releases the write-protection to the data file to be backed up and moves the file written to the virtual file to the data file to be backed up. A write control unit that reads the file information of the data file to be backed up while the write control unit prohibits writing to the data file to be backed up during a backup operation; Based on the information of the backup information file created by the creating backup information creating means for, and the backup information creating means,
Reading a file from the backup target data file and writing it to a backup file,
At the time of completion of writing, a program for functioning as backup control means for notifying the write control means of backup completion is recorded.

According to a fifth aspect of the present invention, there is provided a computer-readable recording medium for inhibiting a computer from writing to a backup target data file in response to a backup request, and writing to the backup target data file. In response to the request, a first write control procedure for writing data to a virtual file different from the backup target data file, and the first write control procedure causes writing to the backup target data file. A backup information creation procedure for reading the file information of the backup target data file during the prohibition and creating a backup information file, and based on the information of the backup information file created by the backup information creation procedure, Read the file from the backup file, write the backup file, the backup control procedure, and when the writing of the backup target data file to the backup file by the backup control procedure is completed, release the write-protection to the backup target data file. A program for executing a second write control procedure for transferring information written to the virtual file to the backup target data file while writing to the backup target data file is prohibited.

According to a sixth aspect of the present invention, there is provided a computer-readable recording medium for inhibiting a computer from writing to a backup target data file in response to a backup request, and writing to the backup target data file. In response to the request, writing to a virtual file different from the backup target data file is performed, and in response to a read request from the backup target data file during the backup operation, If the file exists, read from the virtual file,
A first write control procedure for reading from the backup target data file when the target file does not exist in the virtual file; writing to the backup target data file is prohibited by the first write control procedure A backup information creation step of reading the file information of the backup target data file while creating the backup information file, based on the information of the backup information file created by the backup information creation procedure, A backup control procedure for reading a file from the backup file and writing the backup file to the backup file, and when the writing of the backup target data file to the backup file by the backup control procedure is completed. A second write control procedure of releasing write protection to the backup target data file and transferring information written to the virtual file to the backup target data file while writing to the backup target data file is prohibited. The program to be executed is recorded.

The computer-readable recording medium of the present invention includes a program for causing a computer to function as each unit constituting the backup creation system based on the above-described first aspect of the present invention, or the above-described program of the present invention. A program for causing a computer to execute each procedure constituting the backup creation method based on the second aspect is recorded. Therefore, by executing the recorded program on the computer, the data file to be backed up can be accessed without any trouble even during the backup, and the data file to be backed up is always kept in an optimum state and the type of the backup medium or the like can be determined. Backup can be performed smoothly in a predetermined time.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of a backup creation system according to the present invention will be described with reference to FIGS. FIG. 1 shows the configuration of the backup creation system according to the first embodiment of the present invention.

The backup creation system shown in FIG.
It includes a data input / output unit 1, a write controller unit 2, a data file 3, a virtual file 4, a backup information creation unit 5, a backup information file 6, a backup controller unit 7, a backup file 8, an external device 9, and a console 10. .

The data input / output unit 1 receives a file write request and a file read request from the external device 9 and transmits the information to the write controller unit 2.

When a write request is given from the data input / output unit 1, the write controller 2 constituting the write control means refers to the backup information file 6 in response to the write request, and determines whether the file information exists. , The write information is written to the virtual file 4, and if there is no file information in the backup information file 6, the write information is written to the data file 3. The write controller unit 2 searches for the virtual file 4 in response to the read request, and if the file corresponding to the virtual file 4 exists, the virtual file 4
And if it does not exist in virtual file 4,
Read from data file 3.

Data file 3 to be backed up
When backup is not being executed, file information and data are written and read under the control of the write controller 2 in accordance with write and read requests from the data input / output unit 1. During the execution of the backup, the data file 3 is controlled by the write controller 2, the backup information generator 5, and the backup controller 7, so that the file information and the data are read. Data file 3
After the backup is completed, data is written according to the control of the write controller unit 2.

The virtual file 4 is stored in the write controller 2
According to the above control, the data being backed up is temporarily stored, and the data is read out after the backup is completed.

The backup information creation unit 5 serving as backup information creation means searches for file information indicating a constituent file in the data file 3 and creates a backup information file 6 based on the file information.

The backup controller section 7 constitutes a backup control means, and the backup information file 6
The writing of data from the data file 3 to the backup file 8 is controlled in accordance with the file information stored in the backup file 8. That is, the backup controller unit 7
Reads data from the data file 3 based on the file information of the backup information file 6 and writes the data to the backup file 8.

Data file 3, virtual file 4, backup information file 6, and backup file 8
Is a file constructed in a single or a plurality of divided file devices or each individual file device. The data file 3 is a file for storing data such as a database to be backed up. The virtual file 4 is a file for temporarily storing write data according to a write request at the time of backup. The backup information file 6 is a file for storing file information for managing backup target files, such as configuration file information of the backup target data file 3 to be backed up. The backup file 8 is a file for storing a backup copy of the backup target data file 3.

The external device 9 is a device for accessing the data file 3, and gives a write request to the data file 3 and write data to the data input / output unit 1. 3 is obtained from the data input / output unit 1. The console 10 is a device for instructing a backup of the data file 3 and, when instructing a backup, sends a backup request to the backup information creating unit 5.

Next, the operation of the backup creation system 2 shown in FIG. 1 will be described with reference to the flowcharts shown in FIGS. 2 shows the operation of the backup information creating unit 5, FIG. 3 shows the operation of the write controller unit 2, and FIG. 4 shows the operation of the backup controller unit 7.

First, the operation of the backup information creating section 5 will be described with reference to FIG. The backup information creation unit 5 starts the backup information creation process shown in FIG.

When the backup information creation process is started, the backup information creation unit 5 acquires the backup target information specifying the backup target data file 3 from the console 10 (step S11), and sends the backup information to the write controller unit 2. An instruction is issued to prohibit writing to the target data file 3 (step S1).
2). The backup information creating unit 5 searches the backup information file 6 for file information of the data file 3 to be backed up (step S13), and the file information of the data file 3 to be backed up is stored in the backup information file 6. It is checked whether or not there is (step S14).

If the file information of the data file 3 to be backed up is not stored in the backup information file 6, the file information of the data file 3 to be backed up is constructed in the backup information file 6 (step S15), and the process is terminated. And return to the steady state. If it is determined in step S14 that the backup information file 6 of the file information of the backup target data file 3 already exists, the file information is added to the backup information file 6 (step S16), and the processing is performed. End and return to steady state.

Next, the operation of the write controller 2 will be described with reference to FIG. Write controller 2
Starts write control processing shown in FIG. 3 when write protection is set by the backup information creation unit 5.

When the write control process is started, the write controller unit 2 sets the writing to the backup target data file 3 to be prohibited according to the instruction from the backup information creating unit 5 (step S21), and the data input / output unit It is determined whether the access request given from 1 is a write request to a file in the backup target data file 3 or a read request from a file in the backup target data file 3 (step S2).
2).

When a write request for a file in the data file 3 is received from the data input / output unit 1, the write controller unit 2 changes the write destination of the file to the virtual file 4 and writes (step S23). .
Then, upon receiving the notification of the completion of the backup from the backup controller unit 7 (step S24), the write controller unit 2 transfers the file written in the virtual file 4 to the data file 3 (step S25), The process ends and returns to the steady state.

In step S22, when a request to read a file in the data file 3 is received from the data input / output unit 1, the write controller unit 2 determines whether or not the target file exists in the virtual file 4. 4, the target file is read from the data file 3 if the target file does not exist in the virtual file (step S26).
The process ends and returns to the steady state.

Next, the operation of the backup controller 7 will be described with reference to FIG. The backup controller unit 7 starts the backup control process shown in FIG. 4 when the completion of the creation of the file information is notified from the backup information creation unit 5.

When the backup control process is started, the backup controller unit 7 acquires the backup information file created by the backup information creation unit 5 (step S31), and according to the backup information file 6, backs up the data file 3 to be backed up. Is read (step S32). Backup controller 7
Stores the backup copy of the data file 3 read in accordance with the backup information file in the backup file 8 (step S33). Then, when the backup is completed, the backup controller 7 notifies the write controller 2 of the completion of the backup (step S34), ends the processing, and returns to the steady state. Note that the write controller unit 2
When the backup completion notification is received (see step S24 in FIG. 3), the file saved in the virtual file 4 during the backup is written to the data file 3,
Backup ends.

As described above, when the backup information creating unit 5 receives a backup request from the console 10, an instruction to inhibit writing to the backup target data file 3 is given to the write controller unit 2, and the write controller unit 2 Control is performed so that the write destination of the write request to the data file 3 given from the input / output unit 1 is changed to the virtual file 4.

While the writing to the data file 3 is prohibited by the write controller unit 2, the backup information creating unit 5 reads the information of the data file 3,
A backup information file 6 is created. Based on the backup information of the created backup information file 6, the backup controller unit 7
, And writes the file to the backup file 8.

When the writing to the backup file 8 is completed, the backup controller unit 7 notifies the write controller unit 2 of the completion of the backup, releases the write protection, and the write controller unit 2 writes the data to the virtual file 4. Transfer the file to data file 3. Thus, the backup is completed.

The first effect of the above-described backup creation system is that the target data file 3 is write-protected and the backup information file 6 is created at the time of backup, so that the data file 3 in a unique state at the backup start time is created. Can be backed up.

A second effect of the backup creation system is that the data file 3 is write-protected by the write controller 2 during the backup. For this reason, the backup controller unit 7
When the backup file 8 is created, there is no delay due to a write interrupt while the data file 3 is being read, so that backup can be performed at a predetermined access speed.

FIG. 5 shows the configuration of a backup creation system according to the second embodiment of the present invention. The backup creation system shown in FIG. 5 has the same data input / output unit 1, data file 3, virtual file 4, backup information creation unit 5, backup information file 6,
It includes a backup controller 7, a backup file 8, an external device 9, and a console 10, and further includes a write controller 2A slightly different from the write controller 2 in FIG.

The write controller 2A has the same functions as the write controller 2 in FIG. 1, and further has the following functions.

The write controller unit 2A also checks the files updated after the completion of the entire backup.
When there is a write request from the data input / output unit 1, the file information is given to the backup information creation unit 5,
Information is added to the backup information file 6. Then, after the writing to the data file 3 is completed, the write controller unit 2A prohibits the writing of the file of the data file 3 and the backup controller unit 7 backs up the target file. After the backup is completed, the backup controller 7
Release the write-protection setting of the backup target file for the write controller unit 2A.

A further effect of the backup creation system is that the write controller unit 2A constantly monitors the writing to the data file 3 after the completion of the entire backup, so that the information of the file requested to be written can be instantaneously transmitted. The data can be reflected in the backup information file 6 via the backup information creating unit 5. Therefore, at this point, the backup controller 7 can be operated to perform the backup.

It should be noted that the backup creation system of the present invention can be realized by using a normal computer system without configuring as a dedicated system.
For example, by installing the program from a medium (a floppy disk, a CD-ROM, or the like) storing the program for executing the above-described operation in the computer system, a backup creation system that executes the above-described processing can be constructed. it can. By the installation, the program is stored in a medium such as a hard disk in the computer system, configures a backup creation system, and is used for execution.

Further, the program may be registered in an FTP (File Transfer Protocol) server provided on a communication network such as the Internet, and distributed to an FTP client via the network. The program may be registered in a board system or the like and distributed via a network. Then start this program and run the OS
The above processing can be achieved by executing under the control of the (Operating System). Furthermore, the above-described processing can also be achieved by starting and executing the program while transferring the program via the communication network.

[0054]

As described above, according to the present invention,
A backup creation system that does not hinder access to the data files to be backed up during backup, always allows the data files to be backed up to be in an optimal state, and smoothly backs up the data files for a predetermined time regardless of the type of backup media. A method and a recording medium can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a backup creation system according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of a backup information creation unit in the backup creation system of FIG. 1;

FIG. 3 is a flowchart for explaining an operation of a write controller unit in the backup creation system of FIG. 1;

FIG. 4 is a flowchart illustrating an operation of a backup controller in the backup creation system of FIG. 1;

FIG. 5 is a block diagram illustrating a configuration of a backup creation system according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram showing a configuration of a conventional backup creation system.

FIG. 7 is a flowchart illustrating an operation of the backup creation system of FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 data input / output unit 2 write controller unit 3 (backup target) data file 4 virtual file 5 backup information creation unit 6 backup information file 7 backup controller unit 8 backup file 9 external device 10 console 2A write controller unit

Claims (10)

[Claims] The present invention controls writing of a data file to be backed up, inhibits writing to the data file to be backed up during a backup operation, and responds to a write request to the data file to be backed up. While writing to a virtual file different from the above, when the completion of the backup is notified, the write-protection to the backup target data file is released, and the file written to the virtual file is moved to the backup target data file. Write control means for replacing, and during a backup operation, reading the file information of the data file to be backed up while the write control means prohibits writing to the data file to be backed up, and reading the backup information file. A backup information creating unit to be created; a file that is read from the backup target data file based on the information of the backup information file created by the backup information creating unit; the file is written to a backup file; Backup control means for notifying the means of backup completion. 2. The write control means, in response to a read request from the backup target data file at the time of the backup operation, reads from the virtual file if the target file exists in the virtual file. 2. The backup creation system according to claim 1, further comprising means for reading from the backup target data file when the target file does not exist in the virtual file. 3. When a write request to the data file to be backed up occurs after the completion of the backup, the write control means gives the file information to the backup information creating means, and terminates the write based on the write request. The backup information creating means includes a means for performing a backup operation later, and when the file information requested to be written is received from the write control means, the file information is added to the backup information file via the backup information creating means. 3. The backup creation system according to claim 1, further comprising means for performing backup. 4. A write request to a backup target data file is prohibited in response to a backup request, and a write request to the backup target data file is sent to a virtual file different from the backup target data file. A first write control step of causing writing, and the first write control step reads file information of the backup target data file while writing to the backup target data file is prohibited, A backup information creating step of creating a backup information file; and reading a file from the backup target data file based on the information of the backup information file created in the backup information creating step. Writing to the backup target data file when writing of the backup target data file to the backup file is completed by the backup control step, and writing to the backup target data file A second write control step of transferring information written in the virtual file during the prohibition to the backup target data file. 5. In response to a read request from the backup target data file during the backup operation, if the target file exists in the virtual file, reading is performed from the virtual file, and the target file is stored in the virtual file. 5. The backup creation method according to claim 4, further comprising a step of reading from the backup target data file when the backup does not exist. 6. When a write request to the backup target data file occurs after the completion of the backup,
Adding the file information to the backup information file; prohibiting writing to the backup target data file after the completion of the writing based on the write request; and for writing to the backup target data file, Reading a file from the backup target data file based on the information of the backup information file to which file information has been added, and writing the file to a virtual file different from the backup target data file. Writing to the backup target data file, and when the writing of the backup target data file to the backup file is completed, the write-protection to the backup target data file is released. Backup creation method according to claim 4 or 5, characterized in that it further comprises a step of transferring the information the written to the virtual file while writing prohibition to-yl in the backup target data file, a. 7. A computer controls writing of a data file to be backed up, prohibits writing to the data file to be backed up during a backup operation, and responds to a write request to the data file to be backed up. When writing to a virtual file different from the target data file and the completion of backup is notified,
Write control means for releasing write protection to the backup target data file and transferring the file written to the virtual file to the backup target data file; during a backup operation, the write control means Reading the file information of the data file to be backed up while prohibiting writing, backup information creating means for creating a backup information file, and based on the information of the backup information file created by the backup information creating means, A backup control unit that reads a file from the backup target data file, writes the file into the backup file, and notifies the write control unit of the completion of the backup when the writing is completed; A computer-readable recording medium on which a program for functioning as a computer is recorded. 8. A computer that controls writing of a data file to be backed up, prohibits writing to the data file to be backed up during a backup operation, and responds to a write request to the data file to be backed up. Write to a virtual file different from the target data file, and read the virtual file if the target file exists in response to a read request from the backup target data file during the backup operation. When the target file does not exist in the virtual file, read from the backup target data file, and when the completion of backup is notified, release the write-protection to the backup target data file, Write control means for transferring a file written to the virtual file to the backup target data file; and during the backup operation, the backup control data file is prohibited while the write control means prohibits writing to the backup target data file. The file information is read from the backup target data file based on the information of the backup information file created by the backup information creating means, and the backup information file created by the backup information creating means. At the time of completion of writing, at the time of completion of writing, a computer-readable recording program for functioning as backup control means for notifying the write control means of completion of backup. Recording media. 9. A computer which, in response to a backup request, prohibits writing to a data file to be backed up and responds to a request to write to the data file to be backed up by a virtual machine different from the data file to be backed up. A first write control procedure for causing a file to be written, the first write control procedure allowing the file information of the backup target data file to be written while writing to the backup target data file is prohibited. Reading, a backup information creating step of creating a backup information file, reading a file from the backup target data file based on the information of the backup information file created by the backup information creating procedure, Backup control procedure burn them,
And when the writing of the backup target data file to the backup file is completed by the backup control procedure, the write protection of the backup target data file is released, and the writing of the virtual file to the backup target data file is prohibited. And a second write control procedure for transferring the information written to the backup target data file to a computer-readable recording medium. 10. A computer which, in response to a backup request, prohibits writing to a data file to be backed up and responds to a request to write to the data file to be backed up by a virtual machine different from the data file to be backed up. While writing to a file, in response to a read request from the backup target data file at the time of the backup operation, if there is a target file in the virtual file, read from the virtual file, A first write control procedure for reading from the backup target data file when the target file does not exist in the virtual file; writing to the backup target data file is prohibited by the first write control procedure Has been Reading the file information of the data file to be backed up and creating a backup information file; reading the file from the data file to be backed up based on the information of the backup information file created by the procedure for creating the backup information Backup control procedure to write to the backup file,
And when the writing of the backup target data file to the backup file is completed by the backup control procedure, the write protection of the backup target data file is released, and the writing of the virtual file to the backup target data file is prohibited. And a second write control procedure for transferring the information written to the backup target data file to a computer-readable recording medium.