JPH11212729A - Duplex disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute the on-line backup of a duplex disk device at a high speed without obstructing the system operation of the duplex disk device. SOLUTION: This duplex disk device is provided with a duplex disk one system 1 for backing up data by an external backup device, the duplex disk one system 2 for which the data of the duplex disk one system 1 are duplexed and a disk I/O control process 5 for temporarily saving remaining data among the data during write to a change data storage part 4 and backing up the data recorded in the duplex disk one system 1 to the backup device in the case that the backup device executes the on-line backup while writing the data to the duplex disk one system 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual disk device for storing data in duplicate.

[0002]

2. Description of the Related Art Conventionally, in a database system which operates for 24 hours, a dual disk device for recording the same information in two disk storage devices has been used in order to improve reliability. During normal system operation, this duplex disk device can write or read information to or from both duplexed disks at any time in response to a request from another system. 2 of this duplex disk device
The state in which information can be written to or read from one disk is called online.

[0003] In this type of duplex disk drive,
For information preservation, information on one of the duplicated disks is automatically backed up to an external backup device, for example, a tape device, at predetermined time intervals while online (online backup).

As described above, in the conventional duplex disk device, the first disk segment system to be backed up to an external backup device and the second disk system in which the contents (information) of the first disk segment system are duplicated. Disk piece system. The second disk segment is not the backup target of the external backup device.

By the way, in this duplex disk device,
If online backup processing happens to be started while information is being written to or read from the first disk piece system, disk I / O contention occurs.

Here, if the conventional processing cannot be stopped, the online backup processing and the conventional processing are executed in a time-sharing manner in parallel with the occurrence of disk I / O contention. The execution speed of each process is significantly reduced.

[0007]

As described above, in the above-described conventional dual disk apparatus, during normal system operation,
In other words, if online backup processing occurs during information writing or information reading processing other than backup processing, contention for disk I / O occurs,
In order to avoid this conflict, it is necessary to cancel one of the processes, but in this type of device, the processes cannot be stopped because both processes are important, and each process is performed in a time-division manner. In this case, there is a problem that the processing speed is significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a dual disk device capable of executing backup processing at high speed without interrupting normal system operation. .

[0009]

In order to achieve the above object, a dual disk drive according to the present invention is characterized in that:
The first disk segment system and the second disk segment system are configured to be duplicated, and while the first and second disk segment systems write or read data in response to a request from others, In a duplicated disk device in which an external backup device backs up data recorded on either the first or second disk piece system, the external storage device may store the external data while the first and second disk piece systems are both processing data. If the backup was performed from the backup device of
An evacuation unit for evacuation of the data being processed, and a control unit for writing the data evacuation by the evacuation unit to any one of the first and second disk systems in the middle of the data processing after the backup is completed. It is characterized by:

The duplicated disk device according to the present invention is constructed by duplicating the first disk piece system and the second disk piece system, and the first and second disk piece systems are connected to each other. In executing a write or read of data in response to a request, an external backup device backs up data recorded on either the first or second disk segment, and at least the first When the external backup device backs up the data of the first disk unit while the disk unit is writing data from another, the remaining data of the data being written by the first disk unit is copied. Saving means for saving, and a system for writing the remaining data saved by the saving means to the first disk system after backup is completed It is characterized by comprising a means.

A duplicated disk device according to a third aspect of the present invention is constructed by duplicating a first disk piece system and a second disk piece system, wherein the first and second disk piece systems are connected to each other. In a duplicate disk device in which an external backup device backs up data recorded on one of the first and second disk systems while writing or reading data in response to a request, the external backup device Is backing up the data of the first disk segment, when there is another data write request to the first disk segment,
The data to be read during the backup is set to the second
Control means for switching to the first disk piece system while switching to the first disk piece system.

That is, in the first aspect of the present invention, the first
When the external backup device performs backup while the second disk segment, that is, both systems are processing data, the first disk segment to be backed up saves the remaining data of the data being processed. The backup data is temporarily saved, and the remaining data saved after the backup is completed is written to the first disk system, so that the backup process can be executed at high speed without interrupting the normal system operation.

According to the present invention, when the external backup device backs up the data of the first disk system while at least the first disk system is writing data from the other, the control means is provided. Saves the remaining data of the data being written by the first disk fragment system to the save unit and backs up the data of the first disk fragment system to an external backup device, and saves the data by the save unit after the backup is completed. Since the remaining data is written to the first piece of disk, disk contention is reduced and online backup can be performed at high speed without hindering disk I / O to the duplexed disk device.

Further, according to the third aspect of the present invention, when an external backup device is backing up data of the first disk system, a data write request is issued to the first disk system from another device. If there is, the control unit switches the data to be read during the backup from the first disk system to be backed up to the second disk system to be non-backed up, so that the data being backed up is changed to the second disk system. At the same time as being backed up from the disk system, data for which a write request has been made from another is written to the first disk system. This allows
Backup processing can be executed at high speed without interrupting normal system operation.

[0015]

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

FIG. 1 is a diagram showing the configuration of a duplex disk drive according to one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes one of a plurality of disk devices in which data is duplicated and recorded, that is, a first disk system, and another backup device such as a tape device. This is a disk device for which data is backed up online to a recording medium. Reference numeral 2 denotes the other duplex disk system, that is, the second disk system, which is a disk device that is not a backup target (non-backup target) of an external tape device as a normal system operation setting. The information (data) of the duplicated disk unit 1 is copied to the duplicated disk unit 2 at predetermined time intervals or every time the contents of the duplicated disk unit 1 are updated, thereby constructing a data duplicated structure. You. Reference numeral 3 denotes a disk I / O control unit, which is a switching unit that switches an input / output destination of data according to a data processing status. Reference numeral 4 denotes a changed data storage unit as a save unit, for example, a large-capacity buffer memory for recording data in a FIFO format. That is, the changed data storage unit 4 has a FIFO queue structure, and the data stored first is output first.
When the online backup is started from an external tape device while data is being written to the duplicated disk single system 1 by the normal system operation, the changed data storage unit 4 saves the remaining data being written. Therefore, it is preferable to use, as the change data storage unit 4, a storage unit having a storage capacity that can at least store data to be written to the dual disk unit 1 at a minimum. After the online backup is completed, the data saved in the changed data storage unit 4 is written to the dual disk unit 1. Reference numeral 5 denotes a disk I / O control process, which controls the disk I / O control unit 3 in response to a request from an external backup device or another device, for example, an information processing device, etc. 2 and a control means for controlling the distribution of data to the changed data storage unit 4. Hereinafter, the operation of this duplex disk device will be described with reference to FIGS.

First, a normal operation of the duplex disk device will be described with reference to FIG.

In this duplex disk device, during normal system operation, that is, when online backup is not performed, writing and reading of data to and from the duplex disk single system 1 are performed at the request of an external information processing device or the like. Data can be read out to the duplicate disk system 2 and the disk system 1 and 2 are controlled by the disk I / O control process 5 as follows.

That is, as shown in FIG. 2, during a normal system operation, the disk I / O control process 5 receives an external data write request and a data read request from the disk I / O control unit. 3 is switched between input and output of data to and from the duplicate disk units 1 and 2 and the changed data storage unit.

For example, when there is a data write request from an information processing device or the like, the disk I / O control unit 3 sends the write data to the side of the dual disk unit 1, whereby
Data is written in the dual disk system 1.

After data has been written to the duplexed disk system 1, that is, when the recorded contents of the duplexed disk system 1 are updated, the disk I / O control unit 3 is controlled by the disk I / O control process 5. , Duplex disk single system 1
, A data transmission path is formed to the duplicate disk system 2. Then, the disk I / O control process 5 instructs the data copy, and the data is copied from the duplicate disk system 1 to the duplicate disk system 2.

On the other hand, when the information processing apparatus requests the single-system disk I / O control unit 3 of the duplex disk apparatus to read data from the dual-disk system 1, the disk I
The I / O control unit 3 is controlled by the disk I / O control process 5 to form a data transmission path from the information processing device to the duplex disk system 1. Then, data corresponding to the data read request of the information processing apparatus is read from the duplex disk unit 1 and output to the external information processing apparatus through the disk I / O control unit 3.

Next, a case where a plurality of processes occur simultaneously in the duplicate disk device will be described.

For example, when an external tape device executes an online backup process of data of the duplicated disk device while the duplicated disk device 1 is writing data from the information processing device, an online backup process from the external tape device is performed. Is generated in the disk I / O control process 5.

Then, the disk I / O control unit 3 is controlled by the disk I / O control process 5 to switch the data input / output destination.

Then, as shown in FIG. 3, the write data that has been sent so far to the dual disk unit 1 to be backed up is now sent to the modified data storage unit 4, and the remaining data being written is Change data storage unit 4
Is stored (temporarily saved).

Due to the change of the data transmission path, the data for online backup is sent from the duplex disk system 1 released from the write state to the external tape device, and the data is backed up.

Next, the operation immediately after the online backup will be described.

When the online backup of the data of the dual disk system 1 is completed, the disk I / O control process 5 controls the disk I / O control unit 3 to switch the data input / output destination.

Then, as shown in FIG. 4, the remaining data temporarily saved in the changed data storage unit 4 is written to the dual disk unit 1.

While the data from the changed data storage unit 4 is being written to the duplexed disk unit 1, the disk I / O control unit 3 sends it to the disk I / O control unit 3 from an external information processing device or the like.
When the data read request is issued, the disk I / O control unit 3 responds to the read request, and the disk I / O control unit 3 sets the data I / O to a non-backup target Switch to the disk system 2 and read data from the duplicated disk system 2. If a data read request is issued to the duplicate disk system 2 from the beginning, the data is read from the duplicate disk system 2 as it is. In addition, if the request is for writing data to the dual disk system 2,
Data is written to the duplex disk system 2 as it is.

Further, while the remaining data is being written from the changed data storage unit 4 to the duplexed disk unit 1, there is a request from the external tape device to the disk I / O control unit 3 for data backup to the duplexed disk unit 1. And the disk I / O because the dual disk 1 is being processed.
The control process 5 controls the disk I / O control unit 3 to
The data is sequentially passed to the changed data storage unit 4 having the IFO function, whereby the changed data storage unit 4 writes the newly input data to itself while reading the remaining data to the dual disk unit 1.

That is, as shown in FIG. 5, in the changed data storage unit 4, the write request data during online backup is stored in the form of a FIFO queue at the position of code A, and the write request data after backup is stored in code. B
Is stored in the form of additional storage in the FIFO queue.

When all of the remaining data has been read out to the duplicated disk unit 1, the disk I / O control unit 5 controls the disk I / O control unit 5 so that the input / output destination becomes the input / output destination before the backup. Returning, the data flow becomes as shown in FIG. 2, and the operation of the system is continued in the original state.

That is, during the online backup processing, the data to be written to the dual disk system 1 to be backed up is accumulated (temporarily saved) in the changed data storage unit 4 in the form of a FIFO queue. As for a data read request to the dual disk unit 1, only data that is backed up from an external tape device is permitted to be read, and other read requests are processed by the non-backup target disk unit 2. . Note that data read and write requests to the dual disk system 2 are processed normally.

As described above, according to the duplexed disk device of this embodiment, while the data is being written from the external information processing device to the duplexed disk system 1, the external tape device sends the data of the duplexed disk system 1 online. When backing up, the remaining data being written is backed up to the changed data storage unit 4, and after the online backup is completed, the backed up remaining data is transferred to the dual disk unit 1
Therefore, online backup can be performed at high speed without stopping or hindering writing and reading to and from the dual disk unit system 1 and without causing disk I / O contention, and the backup time can be reduced. . Further, after the online backup is completed, only the changed data difference during the backup is written to the dual disk unit 1 to be backed up, so that the backed up object can be restored at high speed. On the other hand, when an external tape device makes a data read request from an external information processing device during online backup of data of the dual disk system 1, the data is read from the dual disk system 2. Similarly, if there is a data write request from an external information processing device during an online backup, the data requested to be written is stored in the changed data storage unit 4 and, after the online backup, the changed data storage unit 4 Data is written to the duplex disk system 1.

As a result, the contention of the disks can be reduced and the online backup can be executed at high speed without interrupting the disk I / O to the duplicated disk device.

[0039]

As described above, according to the present invention, a saving means for temporarily saving data is provided, and a first disk piece system to be backed up and a second disk piece system not to be backed up are provided. By changing the flow of data by the difference between the function of the backup disk and the backup unit, the normal system operation of the redundant disk unit is prevented when backup is performed from an external backup device during system operation or vice versa. And the backup process can be executed at high speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a duplex disk device according to one embodiment of the present invention.

FIG. 2 is a diagram showing a normal operation operation in the duplex disk device.

FIG. 3 is a diagram showing an operation during online backup in the redundant disk device.

FIG. 4 is a diagram showing an operation immediately after backup in the duplex disk device.

FIG. 5 is a diagram showing a data storage state of a changed data storage unit of the duplex disk device.

[Explanation of symbols]

1. Duplicated disk single system to be backed up 2: Duplicated disk single system not to be backed up 3: Disk I
/ O control unit, 4 ... change data storage unit, 5 ... disk I /
O control process.

Claims (3)

[Claims] 1. A system in which a first disk segment and a second disk segment are duplicated, and the first and second disk segments write or read data according to a request from another. During execution, in a duplicated disk device in which an external backup device backs up data recorded on either the first or second disk fragment, the first and second disk fragments both process data. During the backup from the external backup device during the backup, the evacuation means for evacuation of the data being processed, and the first or And a control unit for writing data to any one of the second disk segments. 2. A system in which a first disk system and a second disk system are duplicated, and the first and second disk systems write or read data according to a request from another. During execution, in a duplicated disk device in which an external backup device backs up data recorded on either the first or second disk device, at least the first disk device writes data from another device. In the meantime, the external backup device is connected to the first
When backing up data of the disk fragment system, the first disk fragment system saves the remaining data of the data being written, and saves the remaining data saved by the saving device after the backup is completed. And a control means for writing data to the first disk piece system. 3. A system in which a first disk system and a second disk system are duplicated, and the first and second disk systems write or read data according to a request from another. In execution, in a duplicated disk device in which an external backup device backs up data recorded on one of the first and second disk pieces, the external backup device may store the data of the first disk piece. If there is another data write request to the first disk segment while backing up, the data to be read during the backup is switched to the second disk segment and Control means for writing data from the other disk which has received a write request to the first disk system. Location.