JPH02236613A - Disk sharing system - Google Patents

Abstract

PURPOSE:To eliminate complicated exclusive control by transferring data between first and second communication means, and making access to a disk device by a first processing means corresponding to a request from a second processing means. CONSTITUTION:When the first processing means 115 makes access to the disk device 111, the first processing means 115 makes direct access to the disk device 111. When the second processing means 119 makes access to the disk device 111, the request to make access is issued from the second communication means 117 to the first processing means 115. The first processing means 115 makes access to the disk device 111 corresponding to the request. The result of access to the disk device 111 is sent from the first communication means 113 to the second communication means 117. Thus, since the access from the second processing means 119 to the disk device 111 is performed by the first processing means 115 via the second communication means 117 and the first communication means 113, it is possible to dispense with the complicated exclusive control between the first processing means 115 and the second processing means 119.

Description

[Detailed Description of the Invention] [Summary] Regarding a disk sharing system that performs exclusive control when a plurality of processing units share a disk device, a disk device for storing data is provided for the purpose of eliminating complicated exclusive control. and a first communication means for transmitting and receiving data, a first processing means for accessing the disk device, and a second communication means for transmitting and receiving data, and the first processing means provides access to the disk device. a second processing means for sending and receiving data between the first communication means and the second communication means;
The first processing means is configured to access the disk device in response to a request from the second processing means.

[Industrial application field]

The present invention relates to a disk sharing system that performs exclusive control when a plurality of processing devices share a disk device.

[Conventional technology]

In recent years, as computer systems operate 24 hours a day and become larger in scale, the impact of so-called system downs in which computer system operations are interrupted has become greater, and there is an increasing need for highly reliable computer systems that will not go down. ．． One of such highly reliable large-scale computer systems is a multiprocessor system having a plurality of processors. This multiprocessor system is also generally a disk sharing system that shares a disk device.

In a disk sharing system, multiple processors access data on the same disk device and perform processing in parallel. Therefore, when multiple processors access the same data at the same time to guarantee processing results, exclusive control is used to prevent one processor from accessing the data until the other processor completes processing. The conventional disk sharing system will be briefly explained below.

Figures 4 (a) to (C) show the configuration of a conventional disk sharing system. The disk sharing system includes two computers 211,
213 and one disk device 215. Disk device 215 is connected to two computers 211 and 213, respectively.

In the disk sharing system shown in FIG. 4(a), two computers 211 and 213 are connected to each other.

When one of the two computers 211 and 213 attempts to access the disk device 215, the computer 211 and the computer 213 communicate with each other to confirm that the other computer is not accessing the disk device 215. Access. The disk sharing system shown in FIG. 4(b) includes a shared memory 411 that stores the usage status of the disk device 215. Two computers 211 and 213 are each connected to shared memory 411. For example, when the computer 211 uses the disk device 215, the computer 211 checks the shared memory 411 and confirms that the computer 213 is not using the shared memory 411. After this confirmation, the disk device 215 is added to the shared memory 411. Use e.g. flag. Such an operation in the shared memory 411 is called test and set. Thereafter, the computer 211 accesses the disk device 215. When the access is completed, the flag of this shared memory 411 is canceled. When the computer 213 accesses the disk device 215, it checks the shared memory 411 and refers to this flag. If the flag is set, the computer 213 knows that the computer 211 is using the disk device 215, and the computer 213 uses the disk device 215 until the flag disappears.
Wait for processing. If there is no flag, shared memory 41
1, the computer 213 accesses the disk device 215. In FIG. 4(C), a disk controller 413 is provided before the disk device 215, and each of the computers 211 and 213 is connected to the disk device 215 via the desk controller 413.

Two computers 211 and 213 are disk devices 21
5, an exclusive acquisition instruction is issued to the disk control device 413, and in response to these instructions, the disk control device 413 simultaneously acquires the two computers 211, -21.
Give access permission so that 3 does not access.

In this way, disks were shared under exclusive control.

[Problem to be solved by the invention]

By the way, when performing exclusive control in the conventional disk sharing system described above, the method shown in FIG.
The software that performs exclusive control through communication between the two computers 211 and 213 becomes complex and enormous. In the method shown in FIG. 4(b), the shared memory 411 requires functions such as test and set, and the hardware of the shared memory 411 becomes complicated. Figure 4 (C)
The method shown in 1 has a problem in that a disk control device 413 is required. Furthermore, when a disk cache is used for high-speed input/output, there is a problem in that the above-mentioned exclusive control becomes increasingly complex.

The present invention was created in view of these points, and an object of the present invention is to provide a disk sharing system that eliminates complicated exclusive control.

[Means to solve the problem]

FIG. 1 is a principle block diagram of the disk sharing system of the present invention.

In the figure, a disk device 111 stores data.

The first processing means 115 has a first communication means 113 for transmitting and receiving data, and accesses the disk device 111.

The second processing means 119 has a second communication means 117 for transmitting and receiving data, and controls access to the disk device 111 from the first
Request processing to Sendan 115.

Therefore, as a whole, data is transmitted and received between the first communication means 113 and the second communication means 117, and the first processing means 115 sends and receives data from the disk device
11.

[For production]

When the first processing stage 115 accesses the disk device 111, the first processing means 115 directly accesses the disk device l.
1 Access 1. When the second processing device 119 accesses the disk device 111, the second communication means 117 requests the first processing means 115 for access. 1st
The processing means 115 processes the disk device 111 according to this request.
access. The result of accessing the disk device 111 is transmitted from the first communication means 113 to the second communication means 117.
will be sent to.

In the present invention, access from the second processing means 119 to the disk device 113 is provided by the second communication means 1l7 and the first
Since the first processing stage 115 performs the processing via the communication stage 113, there is no need for complicated exclusive control between the first processing means 115 and the second processing means 119.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows the configuration of a disk sharing system in one embodiment of the present invention.

■． Here, the correspondence between the embodiment of the present invention and FIG. 1 will be shown.

The processing means 111 corresponds to the computer 2116 computer 213.

The disk device 113 corresponds to a disk device 215, a disk device i1t3]1, a disk device iffF3 1 2, a disk device 3l3, and a disk device 314. Examples of the present invention will be described below assuming that the above-mentioned correspondence exists. In FIG. 2, a multiprocessor system employing the disk sharing system according to the embodiment of the present invention includes two computers 211 and 213 and a disk device 215. The computer 211 includes a CPU 251, a memory 253,
A CPU 251, a memory 253, which includes a CPU monitoring section 255, a communication control section 257, and an input/output channel device 259.
The communication control unit 257 and the input/output channel device 259 are connected via a bus. Further, the CPU monitoring section 255 is connected to the communication control section 257. Computer 213 has a similar configuration to computer 211.

Disk device 215 is connected to input/output channel device 259 of computer 211 and input/output channel device 1269 of computer 2/3. Also, computer 2
The communication control unit 257 of the computer 213 and the communication control unit 267 of the computer 213 can transmit data at high speed.
For example, SCS I (Small Computer S
system interface).

In the computer 211, for example, the disk device 21
When a command to read a program stored in the disk device 5 occurs, the program is read from the disk device 2 via the input/output channel device 259.
The program stored in 15 is read out.

Further, a case in which the disk device 215 is accessed from the computer 213 will be described below.

In the computer 213, the disk drive i! When a read command for a program stored in 215 occurs,
The (7) CPU 2 61 in the computer 2 1 3 is connected to the computer 21 from the communication control unit 267 via SCSI.
The computer 21 communicates with the communication control unit 257 of the computer 21.
This read command is sent to the CPU 251 in the CPU 1. C
When the PLI 251 recognizes this read command, it executes this read command in the same manner as the procedure for reading a program from the disk device 215 from its own device.

The read program is temporarily stored in the memory 253 in the computer 211 and sent from the communication control unit 257 to the SC
Communication control section 267 of computer 213 via sr
sent to. Computer 213 stores the received program in memory 263.

Note that in normal operation, the line connecting the computer 213 and the disk device 215 is not used. The CPU monitoring unit 265 in the computer 213 of the system ii periodically transmits a signal to the computer 21l via the communication control unit 267, and confirms that a response signal is sent back from the computer 211.

If there is no response signal, the computer 213 detects that the system of the computer 211 has gone down. In response, the CPU monitoring unit 265 notifies the CPU 2 6 1 in the computer 213 that the system of the computer 211 has gone down. Thereafter, access to the disk device 215 in the computer 213 is performed via the input/output channel device 269. Thereafter, the computer 213 performs operations similar to those of the computer 211 during normal operation.

In this way, computer 211 and computer 2
13, input/output commands generated in the computer 213 to the disk device 215 are sent to the computer 2.
It is controlled by the CPU 251 of 11. Accordingly, since all operations with the disk device 215 are apparently processed as input/output commands issued to the computer 211, there is no need for complex exclusive control. Furthermore, in addition to using a high-speed line such as SCSI (or GPIB, etc.) between the communication control units 257 and 267, SCSI is used between the input/output channel device 259 (269) and the disk device 215. Also good. By using SCSI, etc. in this way, the time required for communication is equivalent to the overhead time in conventional exclusive control, and the reduction in throughput due to the use of communication does not become a problem. 3 and FIGS. 3(a) to (C) show another embodiment of the present invention.

FIG. 3(a) shows two computers 211213,
It is equipped with three disk devices 311, 3I2, 313,
The three disk devices 311, 312, and 313 are connected to the computer 211 and the computer 213, respectively.

Input/output to and from the three disk devices 311, 312, and 313 is performed via the computer 21.1. The operation of this disk sharing system is similar to the embodiment described above.

FIG. 3(b) has the same configuration as FIG. 3(a), and 2
Access to the two disk devices 311 and 312 is performed via the computer 211, and the disk device 313
Access to is via computer 213.

In this way, which computer 211 or computer 213 is to be controlled is assigned for each disk device.

The operation is similar to the embodiment described above.

FIG. 3(c) includes two computers 211 and 213 and a disk device 314, and the disk device 314 is connected to the computer 21l and the computer 213.

In this disk sharing system, control is assigned to either the computer 211 or the computer 213 in units of data (files or records) stored in the disk device 314.

For example, file A is accessed via computer 211 and file B is accessed via computer 213.

The operation is similar to the embodiment described above.

In this way, by setting whether to be controlled by the computer 211 or the computer 213 for each disk device or file, more efficient system operation is possible.

VB's ・ノU Also, rl. In “Correspondence between Examples and FIG. 1”,
Although the correspondence between the present invention and the embodiments has been explained, the present invention is not limited thereto, and those skilled in the art will easily realize that there are various modifications.

〔Effect of the invention〕

As described above, according to the present invention, when a disk device is accessed by a plurality of processing means, a predetermined processing means performs these accesses, thereby performing complex exclusive control among the plurality of processing means. This is extremely useful from a practical point of view since it is no longer necessary.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of a disk sharing system according to the present invention. FIG. 2 is a block diagram of a disk sharing system according to an embodiment of the present invention. FIG. 3 is a block diagram of another embodiment of the present invention. is a configuration diagram of a conventional example. In the figure, 111 is a disk device, 113 is a first communication means, 115 is a first processing means, 117 is a second communication means, 119 is a second processing means, 211, 213 are computers, 215, 311, 312, 313, 314 is a disk device, 251.261 is a CPU, 4l 3,263 is a memory, 5,265 is a CPU monitoring unit, 7,267 is a communication control unit, 9,269 is an input/output channel device, 1 is a shared memory, 3 is a disk control device.

Claims (1)

[Claims] (1) A first processing means (115) having a disk device (111) for storing data, a first communication means (113) for transmitting and receiving data, and accessing the disk device (111); a second processing means (119) for requesting access to the disk device (111) from the first processing means (115); Data is transmitted and received between the communication means (113) and the second communication means (117), and the first processing means (11
5) A disk sharing system characterized in that the disk sharing system is configured to access the disk device (111).