JP2665199B2 - Mirrored disk management method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirrored disk management system, and more particularly to a mirrored disk management system for a magnetic disk device of a computer system which requires high reliability of data.

[0002]

2. Description of the Related Art Conventionally, in a computer system, when storing important data such that the loss or loss of data handled by a magnetic disk device as an external storage device has a fatal effect on the entire system, a magnetic disk drive is required. The magnetic disk drive is duplicated in order to avoid the failure of reading and writing of data due to the hardware failure of the device and the hardware failure, and the same data is written to both the magnetic disk devices. Even if it is destroyed, it can be replaced by a file in the other disk device.

[0003] This type of mirrored disk is disclosed, for example, in Japanese Patent Application Laid-Open No. 1-118921. This is information that manages the duplication state of the corresponding disk in the duplicated magnetic disk device itself, that is, state information indicating whether the disk is in a master state, a slave state, or a detached state, and the number of updates of such information. When the status of each disk changes, or when a change instruction is given by an operator, the status of each disk is updated on the table to the status after the change. The operation of each magnetic disk device is controlled using the updated management information of the table.

When the magnetic disk devices are started up, the management information in the table provided in each magnetic disk device is read and compared. If there is a mismatch between the read contents, the management information with the larger number of updates is read. By matching the contents of both tables, the flexibility of system construction is improved.

[0005]

In the above-mentioned conventional mirrored disk, when recovering the volume data of the mirrored disk during a system crash, a system stall, or a system reboot after the system power is turned off, the data on the physical disk must be consistent. Since there are few types of disk states for which the reliability can be determined, it is impossible to determine the physical disk having the latest data, and there is a disadvantage that the reliability of the mirrored disk cannot be improved.

[0006]

SUMMARY OF THE INVENTION The present invention provides a plurality of physical disks, a magnetic disk device for controlling the physical disks, and a plurality of physical disks inserted between the magnetic disk device and a file system for reading and writing data. A mirror disk management method performed by multiplexing the physical disks, wherein disk status information to be updated at the start and end of use of the physical disks, respectively, in unused portions of the system area of the physical disks for each of the plurality of physical disks, The system includes duplicated management information having the same contents including partner disk error information that is updated when access to the physical disk fails in reading and writing data and time information that is updated each time data is written to the physical disk. System reset after a crash, system stall, or system power off Over door at the other disk error information of the duplication management information of the physical disk, time stamp, self-Device
The disk state is updated with reference to the chair number .

[0007] The duplication management information of the physical disk is
Comprising a self-device number that represents the device number of the previous SL physics disc, the mapping information representing the device number of the physical disks mirroring the own physical disks, and a checksum for checking the validity of the duplication management information It is characterized by the following.

[0008]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

Referring to FIG. 1, a computer system 11 includes a magnetic disk device 14 for controlling individual physical disks 15, a mirror disk device 13 for managing a mirrored disk composed of the magnetic disk devices 14, and
And a file system 12 for managing data of the mirror disk device 13.

FIG. 2 is a configuration diagram showing details of the mirrored disk of FIG.

Referring to FIG. 2, the mirrored disk 21
Are physical disks # 1 (22a) and physical disks # 2
(22b), each having a system area 23 in which physical information of a physical disk is stored. Further, the system area 23 stores duplex management information 24 for managing volume data of the physical disks constituting the mirrored disk 21 using the unused portion.

FIG. 3 is a view for explaining the configuration of the duplex management information 24 of FIG.

Referring to FIG. 3, the duplication management information 24 shown in FIG. 2 includes a self-device number 31 representing the device number of the self-physical disk, a time stamp 32 updated each time the physical disk is accessed, Disk status 33 indicating whether the disk is in the middle, mapping information 34 indicating the device number of the disk that is mirrored with its own disk, partner disk error information 35 indicating error information of the mirrored disk, and duplex management. Checksum 36 for checking the validity of the information
It is composed of Also, this duplicate management information
As shown in FIG. 2, two physical disks 22a and 22b having the same contents are provided in preparation for a sector failure of the magnetic disk device.

Next, the operation of the embodiment constructed as described above will be described.

First, when there is a use start request of the mirrored disk 21 from the file system 12 of the computer system 11, the mirror disk drive 13 opens all the physical disks 15 constituting the mirrored disk 21 to the magnetic disk drive 14. Make a request.

When the request to open all the physical disks 15 is completed normally, the mirror disk device 13 sets the disk status 33 of the duplication management information 24 of the physical disks 15 to “ON”, and then sets the file system 1
2, a request to start using the mirrored disk 21 is returned. Thereby, the mirrored disk 21 is mounted.

After the mirrored disk 21 is mounted, if there is a write request to the mirrored disk 21, the mirror disk device 13 sends all the write requests to the physical disk 15 constituting the mirrored disk 21 to the magnetic disk device 14. Then, upon the normal completion of the write request, the mirror disk device 13 updates the time stamps 32 of the duplication management information 24 of all the physical disks 15 constituting the mirrored disk 21 with the updated time.

Next, in response to a read request for the mirrored disk 21, the mirror disk device 13 does not update the time stamp of the duplication management information 24 of the physical disk 15 constituting the mirrored disk 21.

When the mirrored disk 21 is unmounted, the mirror disk device 13 sends all the physical disks 15 constituting the mirrored disk 21 in response to a request to terminate use of the mirrored disk 21 from the file system 12.
The disk status 33 of the duplication management information 24 of the "OFF"
After that, a request to close all the physical disks 15 is made to the magnetic disk device 14. Then, when the request to close all the physical disks 15 is completed normally, the mirror disk device 13 returns a request to end use of the mirrored disk 21 to the file system 12.

In response to a write request from the file system 12 to the mirrored disk 21, the mirror disk device 13 writes all the physical disks 15 to the magnetic disk device 14. If a write error occurs in any of the physical disks 15 in writing to all the physical disks 15, the mirror disk device 13 stores the duplicate management information 24 of the physical disk 15 in which the write error has not occurred. The partner disk error information 35 is set to "ON". This indicates that an error has occurred in the mirrored physical disk 15.

Thereafter, the mirror disk device 13 replaces the mirrored disk 21 with the one-sided physical disk 15 without accessing the physical disk 15 in which the write error has occurred.
Only drive. Therefore, mirrored disk 2
In response to the write request to 1, the time stamp 32 of the duplication management information 24 of the physical disk 15 is updated only for the normal physical disk 15. Mirrored disk 2
In the use end request of No. 1, the disk status 33 of the duplex management information 24 indicates that only the normal physical disk 15 is “OFF”
Is done.

Next, in response to a read request from the file system 12 to the mirrored disk 21, the mirror disk device 13 reads from one of the physical disks 15 constituting the mirrored disk 21 to the magnetic disk device 14. . If a read error occurs during reading from the physical disk 15, the mirror disk device 13 sets the partner disk error information 35 of the duplex management information 24 of the other physical disk 15 to “O”.
N ", and reads from the physical disk 15 to the magnetic disk device 14. The mirror disk device 13 reads the physical disk 15 on which a read error has occurred.
Mirrored disk 2 without any access
1 is to operate only one physical disk 15. The handling of the duplicate management information 24 of the physical disk 15 is the same as the case of writing to the mirrored disk 21.

When the system system reboots and the file system 12 requests the mirror disk 21 to be reused, the mirror disk device 13
Request to open all the physical disks 15 that make up the mirrored disk 21. The mirror disk device 13 searches for an accessible physical disk 15 from the partner disk error information 35 of the duplication management information 24 of the physical disk 15 or whether the open request of the physical disk 15 failed.

Then, the mirror disk device 13 sets the disk status 33 of the duplicate management information 24 of the accessible physical disk 15 to "ON". At this time,
The mirror disk device 13 keeps the inaccessible physical disk 15 in the closed state, so that the mirrored disk 21 operates with only one physical disk 15.

Next, in response to an open request to all the physical disks 15 constituting the mirrored disk 21,
If there is no physical disk 15 in which an error has occurred in the partner disk error information 35 of the duplicate management information 24 of the physical disk 15, the mirror disk device 13 compares the time stamps 32 of the duplicate management information 24 of all the physical disks 15. Then, it is determined whether or not the times are the same.

If the time stamps 32 do not have the same update time, data consistency between the physical disks 15 constituting the mirrored disk 21 is not ensured.
The mirror disk device 13 uses the other physical disk 15 based on the physical disk 15 having the latest time stamp.
Perform volume data recovery.

With the start of the data recovery, the mirror disk device 13 moves the physical disk 1 of the data recovery source.
5, the disk status of the duplex management information 24 is set to “ON”, and the disk status 33 of the data recovery destination is set.
Set to "Recovering". When the recovery of the volume data is completed, the mirror disk device 13
Changes the disk status 33 of the duplex management information 24 of the data recovery destination physical disk 15 from “recovering” to “O
N ", and the mirroring operation of the mirrored disk 21 is started.

When the time stamp 32 of the duplication management information 24 of the physical disk 15 constituting the mirrored disk 21 has the same update time, the mirror disk device 1
3 examines the disk status 33 of the duplicate management information 24 of the physical disk 15. Then, when the disk status 33 of both physical disks 15 is “OFF”, the mirror disk device 13 sets the disk status of the duplex management information 24 of the physical disk 15 to “ON”, and the mirrored disk 2
Start the mirroring operation of No. 1. If the disk status 33 of the duplication management information 24 of one of the physical disks 15 is “ON”, the unmounting of the mirrored disk 21 is not completed due to a system crash, a system stall, a power failure, or the like. 2
There is a possibility that data consistency between the physical disks 15 constituting the first disk is not maintained.

Therefore, the mirror disk device 13 uses the physical disk 15 whose disk status 33 in the duplex management information 24 is “OFF” as a data recovery source and the physical disk 15 whose disk status 33 is “ON” as a data recovery destination. Perform volume data recovery. When the data recovery starts, the mirror disk device 13
The disk status 33 of the duplex management information 24 of the data recovery source physical disk 15 is set to “ON”,
The same disk status 33 of the recovery destination is set to “recovering”.

When the recovery of the volume data is completed, the mirror disk device 13 sets the disk status 3 in the duplex management information 24 of the physical disk 15 as the data recovery destination.
3 is changed from “recovery” to “ON”, and the mirroring operation of the mirrored disk 21 is started.

Similarly, when the disk status 33 of the duplication management information 24 of both physical disks 15 is “ON”, the unmounting of the mirrored disk 21 has not been completed due to a system crash, system stall, or power-off, etc. Physical disk 1 constituting disk 21
There is a possibility that data consistency is not maintained between the five.

Accordingly, the mirror disk device 13 uses the physical disk 15 having the smaller device number of the own device number 31 of the duplex management information 24 as the data recovery source, and the physical disk 1 having the larger device number of the own device number 31.
5 is used as a data recovery destination to recover the volume data. When the data recovery is started, the mirror disk device 13 changes the disk status 33 of the duplex management information 24 of the data recovery source physical disk 15 to “O”.
N "and the recovery destination physical disk 1
The disk status 33 of the duplication management information 24 of No. 5 is set to “recovering”.

When the recovery of the volume data is completed, the mirror disk device 13 sets the disk status 33 of the duplication management information 24 of the physical disk 15 as the data recovery destination.
Is changed from “recovery” to “ON”, and the mirroring operation of the mirrored disk 21 is started.

[0035]

As described above, according to the present invention, the volume data of a mirrored disk is checked in three stages using the partner disk error information, the time stamp, and the disk status of the duplication management information of the physical disks constituting the mirrored disk. As a result, when the data consistency between the physical disks constituting the mirrored disk cannot be determined due to a system crash, system stall, power failure, or the like, the reliability of the volume data of the mirrored disk can be improved. is there.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a configuration diagram showing details of a mirrored disk of FIG. 1;

FIG. 3 is a diagram for explaining a configuration of duplex management information of FIG. 2;

[Explanation of symbols]

 11 Computer System 12 File System 13 Mirror Disk Device 14 Magnetic Disk Device 15 Physical Disk 21 Mirrored Disk 22a, 22b Physical Disk 23 System Area 24 Duplex Management Information 31 Own Device Number 32 Time Stamp 33 Disk Status 34 Mapping Information 35 Remote Disk Error Information 36 Checksum

Claims (2)

(57) [Claims] 1. A plurality of physical disks, a magnetic disk device for controlling the physical disks, and a mirror disk inserted between the magnetic disk device and a file system for multiplexing data reading and writing on the plurality of physical disks A management method, wherein in each of the plurality of physical disks, an unused portion of a system area of a physical disk is updated by starting and ending use of the physical disk, and by reading and writing data to and from the physical disk. It has duplicated management information of the same contents, consisting of partner disk error information that is updated when access fails and time information that is updated each time data is written to the physical disk. System crash, system stall, and system power off Duplicate physical disk in later system reboot Refer to the partner disk error information, time stamp, and local device number in the
A mirrored disk management method characterized by updating the disk status . Duplication management information as claimed in claim 1, wherein the physical disk, before Symbol
And own device number indicating the device number of the physical disk, the mapping information representing the device number of the physical disks mirroring the own physical disk, further comprising a checksum for checking the validity of the duplication management information 2. The mirrored disk management system according to claim 1, wherein: