JPH045211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention The present invention relates to a magnetic disk control device that writes update data to a magnetic disk file in response to a data update request, and particularly to a magnetic disk control device that writes the same update data to primary and secondary magnetic disk files separately in response to a data update request. This invention relates to a dual-write magnetic disk control device.

Prior Art In recent years, magnetic disk devices have become fixed media and have a larger capacity, and are therefore widely used as online files.

When a magnetic disk is used as a large-capacity online file like this, conventionally data was written on the magnetic disk in a single manner, so if a failure occurs in the magnetic disk device, it is difficult to deal with it on a daily or weekly basis. Create a backup file in advance and save it, and when an online magnetic disk device failure occurs, load this backup file onto another magnetic disk device, catch up with the current day's journal file, and execute that process to resolve the problem. It was necessary to take steps to recover the Therefore, in the past, there was a problem in that when a failure occurred in an online magnetic disk device, a huge amount of time and effort was required to recover from the failure.

Therefore, conventionally, a dual write method has been considered in which the magnetic disks used as online files are duplicated and the same update data is written separately onto the disks.

The above methods include those using software and those using hardware. Among these, the method using software executes the above-mentioned double writing in the central processing unit, which increases the software overhead and reduces the overall system load. There is a problem that the performance of the primary and secondary magnetic disk files decreases, and in this respect, dual writing processing using hardware is effective.In particular, methods in which dual writing processing is performed on the magnetic disk control device side are effective in reducing the combination of primary and secondary magnetic disk files. It is suitable in that it can be placed under the control device at will.

However, in conventional systems in which the above-mentioned double write processing is performed on the magnetic disk controller side, the data path from the central processing unit to the magnetic disk file is simply duplicated and the double write processing is performed. The system is a single system, and when the data path fails, the above-mentioned double write processing is no longer performed and the double write data cannot be stored on the magnetic disk, which poses a problem in maintaining the reliability of the system. It was hot.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to be able to continue to perform the dual write processing even if a failure occurs in the data path from the central processing unit to the magnetic disk device. An object of the present invention is to provide a dual-write magnetic disk control device.

General Description of the Invention In order to achieve the above object, the present invention has a plurality of directors including a plurality of data path systems from a central processing unit to primary and secondary magnetic disk files, and has a data update request from the central processing unit. The updated data from the central processing unit is transferred to the positive magnetic disk file via any one of the data path systems of the plurality of directors, and the updated data is stored, and any director among the plurality of directors is stored. The present invention is characterized in that the updated data is sent to the sub-magnetic disk file via either data path system, and the updated data can be written twice by any director.

Embodiments of the Invention Hereinafter, preferred embodiments of a dual-write magnetic disk control device according to the present invention will be described with reference to the drawings.
In this embodiment, in order to simplify the explanation, two directors having two data path systems will be taken as an example.

FIG. 1 shows the configuration of a system including a dual-write magnetic disk device according to the present invention.
Further, FIG. 2 shows the internal block configuration of the dual-write magnetic disk control device in the system shown in FIG.

In FIG. 1, channel devices 12A and 12B are provided on the upper side of the dual-write magnetic disk control device 10.
A central processing unit 14 is connected via the central processing unit 14 . Further, on the lower side of the dual-write magnetic disk controller 10, a large number of magnetic disk drive devices 18-1, 1 are connected via a large number of magnetic disk connection devices 16A, 16B.
8-2,... are connected.

The magnetic disk drive device 18-1 can write updated data to the positive magnetic disk file 20A, and the magnetic disk drive device 18-2 can write the same updated data to the sub magnetic disk file 20B.

As described above, the data path system from the central processing unit 14 to the primary and secondary magnetic disk files 20A and 20B via the channel devices 12A and 12B, the dual-write magnetic disk control device 10, and the disk connection devices 16A and 16B is In the embodiment, there are two systems.

Further, in the present invention, the dual-write magnetic disk control device 10 has a pair of directors 22A and 22B,
The directors 22A and 22B are connected to the two data path systems and configured as follows.

In this embodiment, the directors 22A, 22B
are connected to the central processing unit 14 via channel switches 24A and 24B, respectively. The channel switches 24A and 24B can switch the directors 22A and 22B to central processing units of other channels.

Further, in the present invention, the directors 22A, 22
B can independently perform the double writing,
For this reason, the dual-write magnetic disk control device 10 of this embodiment is configured as follows.

In FIG. 2, the dual-write magnetic disk control device 10 is provided with channel switches 24A, 24B and data paths 26A, 26B connected to disk connection devices 16A, 16B, respectively. Two systems of data paths leading to the magnetic disk files 20A and 20B are ensured.

Each director 22A of the dual-write magnetic disk controller 10 includes two data buffers 28A-1,
28A-2, 28B-1, 28B-2 are provided, and the data buffer 28 of the director 22A is
A-2, data buffer 28 of director 22B
B-2 is connected to the data paths 26A and 26B, respectively, via a data path 26C-1. These data buffers 28A-2 and 28B-2 can store updated data from data path 26A, and can send the stored updated data onto data paths 26A and 26B, respectively.
Data buffers 28A-1 and 28B-2 also connect to the data path 26C-2 via the data path 26C-2.
A, 26B is connected, and data buffer 2
8A-1 and 28B-1 can store updated data from data buffer 28B and can send the updated data to data paths 26A and 26B, respectively.

Then, the directors 22A, 22B take in the data from the control memories 30A, 30B storing the access control data of the data buffers 28A, 28B and the control memories 30A, 30B via the dual write control data path 32, Queue buffers 34A and 34B are provided, respectively, for controlling the write order of updated data based on the captured data.

A preferred embodiment of the present invention has the above configuration,
The effect will be explained below.

When a data update request is given from the central processing unit 14 to one of the directors 22 via the channel device 12, the director 22 updates the data via its magnetic disk connection device 16, that is, via one of the data path systems. , gives the updated data to the magnetic disk drive device 18-1, and causes it to record the updated data in the positive magnetic disk file 20A. At the same time, the director 22 writes the same update data to the data buffers 28A, 28B of both directors 22A, 22B, and when the writing is completed, queues the data update request to both queue buffers 34A, 34B.

After that, the other director-free director 22 that is not performing an I/O operation searches for a data update request stored in its queue buffer 34, and drives the magnetic disk drive device 18-2 in accordance with the update request. The update data given by the central processing unit 14 is written to the sub magnetic disk file 20B.

Here, if a failure occurs that makes either of the directors 22A, 22B in the present dual-write magnetic disk control device 10 inoperable, and the other operable director 22 becomes director-free, the director 22 The updated data is taken out from the data buffer 28 onto the data path 26, and the updated data is given to the magnetic disk drive unit 18-2 to update the data in the sub magnetic disk file 20B.

Next, an example of the above processing operation will be explained using FIG.

In FIG. 3, a positive magnetic disk file 20 is sent from the central processing unit 14 to the director 22A.
When a data update request is issued for A, the director 22A updates the positive magnetic disk file 20A.
The transfer data is positioned and data is written into the data buffers 28A-2 and 28B-2.

After writing to the magnetic disk file 20A is completed, the director 22A positions the sub magnetic disk file 20B when it is free, and writes data to the data buffer 28B-2.

If a failure occurs in the director 22B while the above-mentioned data is being written, the function of the director 22B will stop and data writing cannot be continued, but in this case, the director 22A will start operating and the The records in the magnetic disk file 20B are positioned, data is taken out from the data buffer 28A-2, and the data is written. In this way, even if a failure occurs in one of the directors 22, the same data will be written to the primary and secondary magnetic disk files 20A and 20B, and this dual writing process will not be interrupted.

In addition, in this embodiment, both directors 22A, 22
A data buffer 28 and a queue buffer 34 are separately provided in B, and both directors 22A and 22B can use them independently, so even if there is a bias in the I/O order of both directors 22A and 22B, there is no director free operation. Any one of the directors 22 can transfer updated data from the data buffer 28 to the sub magnetic disk file 20B, thereby improving system throughput.

Effects of the Invention As explained above, according to the present invention, a plurality of directors capable of independently performing the dual writing are provided in a plurality of data path systems from the central processing unit to the primary and secondary magnetic disk files. Because there are
Even if a failure occurs in one of the directors, the updated data can be written to the secondary magnetic disk file by another director that is capable of dual writing operation, and the updated data can continue to be written twice, thus improving system reliability. can be improved.

Further, according to the present invention, the double write operation can be performed without changing the software, so the overhead of the software does not increase and the performance of the system does not deteriorate.

Furthermore, it is also possible to transfer data from the data buffer of each director to the central processing unit via the channel device, or from the magnetic disk drive side to the data buffer of each director. It can also be used as a device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a system using a dual-write magnetic disk control device to which the present invention is applied, and FIG.
FIG. 1 is an internal block diagram of the dual write magnetic disk control device, and FIG. 3 is an explanatory diagram of the double write processing operation. 10... Dual write magnetic disk control device, 14...
...Central processing unit, 20A... Positive magnetic disk file, 20B... Sub-magnetic disk file, 22
A, 22B...Director, 26...Data buffer, 34...Kyu buffer.

Claims (1)

[Claims] 1 A plurality of data paths connected from a central processing unit to primary and secondary magnetic disk files, each having a data buffer for storing update data from the central processing unit and a queue buffer for storing data update requests from the central processing unit. a director, in response to a data update request from the central processing unit, the updated data is transferred to the positive magnetic disk file via one of the plurality of directors, and the updated data is transferred to the data buffer of the director and to the other director. The data update request is stored in the data buffer of the director, and the data update request is stored in the queue buffer of the director concerned and the queue buffer of other directors, and after that, any director among the plurality of directors stores the data in the data buffer in accordance with the data update request stored in the queue buffer. A dual-write magnetic disk controller characterized in that the updated data sent to the sub-magnetic disk file is sent to the sub-magnetic disk file via one of the data paths.