JPH04241016A - Mirrored disk device - Google Patents

Abstract

PURPOSE:To eliminate the need for subsequent rewriting and facilitate management and control by writing data even on a newly installed disk device being an object of a recovery process when the writing is possible even halfway in the recovery process of data. CONSTITUTION:A mirrored disk controller 4 controls the multiple reading and writing of data on plural disk devices 21-2n at a request from a computer system 6. Further, data are recovered from the normal disk 21 during the recovery replacement of a disk device 2i which is disconnected owing to a fault. If a normal write request is made during the recovery process of data, writing is carried out including the recovered and replaced disk device 2i when the writing targets the recovered data judging from control information of a data recovery control mechanism 5 or on the disk devices except the recovered and replaced disk device 2i when unrecovered data is targetted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirrored disk device in an electronic computer system.

0002

[Background Art] In electronic computer systems that require high reliability, multiple disk devices are installed to prevent errors from occurring in data stored in disk devices such as magnetic disk devices and optical disk devices. Efforts are being made to improve reliability. Such a disk device is called a mirrored disk device.

[0003] The operation of a conventional mirrored disk device will be explained by case.

(1) Data writing Data is written from a computer system to all of a plurality of disk devices. If there is a disk device for which writing has failed, isolate the disk device as a failure, repair and restore it, or replace it with a normal disk device, and stop writing to that disk device until the data recovery process is complete. .

(2) Data reading Data is read from one of a plurality of disk devices. If this reading fails, the disk device is disconnected as a failure and is not used for reading until data recovery is completed by recovery or replacement. Then, reading is performed again from one of the other disk devices. If it fails, repeat the same process.

(3) Data recovery When a disk device that has been disconnected due to a failure is repaired and restored, or when it is replaced with a normal disk device,
In order to match the data contents with other disk devices, the data is transferred from one of the normal disk devices to the recovered/replaced disk device and copied (written). When data recovery is complete, the disk device is reinstalled into the system and used for writing and reading.

[0007]

[Problem to be solved by the invention] As explained above,
With conventional mirrored disk devices, the same data is stored on multiple disk devices, and the probability of all disk devices failing at the same time is extremely low, so high data reliability can be ensured. , it had the following drawbacks:

In other words, in a conventional mirrored disk device, when a data write request is received from a computer system during data recovery processing, the recovered/replaced disk device that is the target of data recovery processing is does not write. This is because a disk device undergoing recovery processing cannot be equated with other normal disk devices.

[0009] Therefore, in a conventional mirrored disk device, even if the data recovery process is completed, the data content is different from that of other disk devices at that point, and the data may not be written to the other disk device during the recovery process. The data must be further written to the disk device on which the recovery process has been completed, and in systems where data is frequently written, managing that data becomes complicated.

[0010] The present invention has been proposed in view of the above points, and its purpose is to restore or replace data that is the subject of data recovery, if possible, even during the process of data recovery. Data is also written to the disk device,
An object of the present invention is to provide a mirrored disk device that can eliminate the need for subsequent rewriting.

[0011]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of disk devices, a plurality of disk control devices that control the plurality of disk devices, and a disk drive system that controls a plurality of disk devices when the disk device is restored or replaced. A data recovery management mechanism that manages the extent to which device data has been recovered, controls multiplexed reading and writing of data to multiple disk devices, and recovers data from a normal disk device when recovering or replacing a disk device. If a normal write request occurs during data recovery processing, if it is a write to data that has already been recovered, judging from the management information of the data recovery management mechanism, it will be processed, including the disk device that was recovered or replaced. The mirrored disk control device performs writing, and controls the writing to be performed on a disk device other than the recovered or replaced disk device if writing is to unrecovered data.

0012

[Operation] In the mirrored disk device of the present invention, the mirrored disk control device controls multiplexed reading and writing of data to a plurality of disk devices in response to requests from a computer system, and also controls the multiplexed reading and writing of data to a plurality of disk devices in response to requests from a computer system. Control is performed so that data is recovered from a normal disk device, and if a normal write request occurs during data recovery processing, the data will be recovered if it is written to data that has already been recovered, as determined from the management information of the data recovery management mechanism. - Write is performed including the replaced disk device, and if writing is for unrecovered data, control is performed to write to a disk device other than the recovered/replaced disk device.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a mirrored disk device of the present invention.

In FIG. 1, the mirrored disk device 1 of this embodiment is connected to a computer system 6, and writes/reads data in response to a data write/read request from the computer system 6. There is.

On the other hand, the internal configuration of the mirrored disk device 1 includes a plurality of disk devices 21 to 2n, a plurality of disk control devices 31 to 3n that control the plurality of disk devices 21 to 2n, and a plurality of disk control devices 31 to 3n that control the plurality of disk devices 21 to 2n. The mirrored disk control device 4 that controls the entire system, and the disk device (21 to 2n) when the disk device (21 to 2n) is restored or replaced.
1 to 2n) is provided. A data recovery management mechanism 5 is provided to manage the extent to which data recovery has been performed.

[0017] The operation of the above embodiment will now be explained in different cases.

(1) Writing data When the computer system 6 requests the mirrored disk device 1 to write data, the mirrored disk control device 4 removes the disk device that has been disconnected due to a failure at that time. The same data is written to all the disk devices 21 to 2n via the disk control devices 31 to 3n. If there is a disk device for which writing has failed, disconnect that disk device as a failure and
Stop writing to the disk device until it is repaired and restored, or until it is replaced with a normal disk device. For example, if writing to the disk device 2i fails, the disk device 2i is considered to be faulty and disconnected.

(2) Data reading When the computer system 6 requests the mirrored disk device 1 to read data, the mirrored disk control device 4 removes the disk device that has been disconnected due to a failure at that time. Data is read from one of the plurality of disk devices via the corresponding disk control device. For example, if the disk device 2i is disconnected due to a failure, data is read from one of the other normal disk devices, for example, the disk device 21. If this reading fails, the disk device is separated as a failure and is not used for reading until it is restored or replaced. Then, reading is performed again from another disk device. If it fails, repeat the same process.

(3) Data Recovery When a disk device that has been disconnected due to a failure is repaired and restored, or replaced with a normal disk device and reincorporated into the system, the mirrored disk control device 4 saves the data contents to other sources. In order to make the data match the disk device of the original disk device, data is transferred from one of the normal disk devices to the restored/replaced disk device via the corresponding disk control device, and the data is copied. For example, when the disk device 2i that was disconnected due to a failure is reincorporated due to restoration or replacement, data is copied from one of the other normal disk devices, for example, the disk device 21.

FIG. 2 is a flowchart showing the procedure of the above data restoration process. That is, it is checked whether or not the recovery of all data has been completed (steps S1, S2), and if it has not been completed (NO in step S2), the data in the normal disk device is read in a predetermined unit (step S3). ), writes the data to the newly installed disk device (step S4), and registers the transferred data area in the data recovery management mechanism 5 (step S5). Then, it is checked again whether the restoration of all data has been completed (steps S1 and S2), and if it has not been completed (step S
If NO in step S2), the same process is repeated, and if completed (YES in step S2), the process ends.

(4) Writing data when restoring data;
The most characteristic operation of the present invention is that when there is a data write request from the computer system 6 during the data recovery process described above, the mirrored disk control device 4 temporarily suspends the data recovery process and manages the data recovery. Referring to the management information of the mechanism 5, if the write is to data that has already been recovered, the write is performed to all disk devices 21 to 2n, including the disk device that has been recovered or replaced, and if the write is to data that has not been recovered, the write is performed to all disk devices 21 to 2n. Write to a disk device other than the recovered or replaced disk device.

FIG. 3 is a flowchart showing the processing procedure when a data write request is received from the computer system 6 during the data recovery process described above. That is,
First, the mirrored disk control device 4 writes data to a plurality of other disk devices that are not used for data recovery (step S6). for example,
When data is being restored from a normal disk device 21 to the restored/replaced disk device 2i, data is written to a disk device other than the disk devices 21 and 2i.

[0024] Next, referring to the information of the data recovery management mechanism 5, it is checked whether the data area targeted for the write request is an area for which data recovery has already been completed (steps S7 and S8). .

[0025] If data recovery has already been completed (YES in step S8), it means that the data in that area already matches and is synchronized with other disk devices; The same data is written to the disk device used for recovery (step S9), and the process ends. For example, when data is being restored from a normal disk device 21 to the restored/replaced disk device 2i, data is written to the disk devices 21, 2i.

On the other hand, if data recovery is not completed (
If NO in step S8), the data in that area is not synchronized with other disk devices, so the disk device that is the target of recovery is excluded, and the data transfer source for recovery is The same data is written only to the disk device that is (step S1
0), the process ends. For example, when data is being restored from a normal disk device 21 to the restored/replaced disk device 2i, data is written only to the disk device 21.

[0027] When the writing of the above data is completed,
The interrupted data recovery process will be resumed. and,
If data is written to an area for which data recovery has not been completed during the interruption, that data will be reflected in the recovered/replaced disk device as part of the recovery process.

[0028] When the data recovery process is completed, the disk device is again used as a target for multiplexed writing and reading in the same way as usual.

[0029]

As explained above, in the mirrored disk device of the present invention, even if the incorporated disk device is in the middle of data recovery processing, if the data is written to data that has already been recovered, the recovery process can be performed. Since data will also be written to the disk device targeted for
When the data recovery process is completed, the data contents will be completely consistent with those on other disk devices, and there is no need for subsequent rewriting as in the past, so management and
This has the effect of making control very easy.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a mirrored disk device of the present invention.

FIG. 2 is a flowchart showing processing at the time of data recovery in the embodiment.

FIG. 3 is a flowchart showing processing when a write request is received from a computer system during data recovery in the embodiment.

[Explanation of symbols]

1...Mirrored disk devices 21 to 2n...Disk devices 31 to 3n...Disk control device 4...Mirrored disk control device 5...Data recovery management mechanism 6...Computer system

Claims (2)

[Claims] Claim 1: A plurality of disk devices, a plurality of disk control devices that control the plurality of disk devices, and a data recovery system that manages the extent to which the data of the disk device has been recovered when recovering or replacing the disk device. In addition to controlling the management mechanism and multiplexed reading and writing of data to multiple disk devices, it also controls data recovery from a normal disk device when recovering or replacing a disk device, and performs normal writing during data recovery processing. When a request occurs, judging from the management information of the data recovery management mechanism, if the write is to data that has already been recovered, the write will be performed including the recovered/replaced disk device, and if the write is to unrecovered data, the write will be performed using the recovered/replaced disk device. A mirrored disk device comprising: a mirrored disk control device that controls writing to a disk device other than the replaced disk device. [Claim 2] During data recovery processing, the mirrored disk control device registers the area of written data in the data recovery management mechanism each time data read from a normal disk device is written to a recovered or replaced disk device. The mirrored disk device according to claim 1.