JPH07104945A - Copy processing method - Google Patents

Abstract

(57) [Summary] [Purpose] To enable efficient copy processing without burdening business programs. [Structure] An input / output control device having a duplicated external storage device and a buffer, a copy processing unit for controlling these and a firmware provided with a flag, and a copy process is easily performed in the input / output control device by flag control. I do. In this case, the I / O activation instruction from the business program is prioritized, and the copying process is performed when there is no I / O activation instruction. As a result, the copying process can be efficiently executed only within the input / output device, and the business program is not affected at all.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when copying data from an external storage device such as a magnetic disk device to another external storage device, does not interrupt the execution of a business program and secures a buffer. The present invention relates to a copy processing method that can be performed.

[0002]

2. Description of the Related Art Conventionally, when copying the contents of an external storage device A incorporated as a duplicated memory, for example, Japanese Unexamined Patent Application Publication No. Hei.
As described in Japanese Patent Laid-Open No. 115321, a copy processing unit is provided on the upper side (upper program) of the input / output control device, and input / output startup by a business program and input / output startup by the copy processing unit are alternately performed. As a result, the copy process is performed without interrupting the execution of the business program. That is, when the copy processing unit issues a chain command to the input / output control unit, the input / output control unit executes a read command and a command to the external storage device A, and then a write command to the external storage device B. Is issued continuously. Until the chain command is completed, since the input / output control unit exclusively controls the external storage device A, programs other than the copy processing unit do not interrupt the external storage device A to write the data, and the copy is completed. The identity of the data in both external storage devices A and B is guaranteed. When a business program operating in parallel writes data to the external storage device A during copying, the input / output control unit writes the data to the external storage device B. The identity of the contents of A and the external storage device B can be guaranteed.

[0003]

However, in the above-mentioned prior art, it is necessary to secure a buffer area for copy processing in both the copy processing section and the main storage device which can be processed in parallel with the business program. . Further, the copy processing section needs a measure such as suppressing an input / output interrupt from a business program during the copy processing in order to guarantee the sameness of data in the duplicated external storage devices A and B. If the copy process is executed during the program execution, there is a problem that the process of the business program is delayed. An object of the present invention is to solve these conventional problems, and it is not necessary to secure a buffer area for copy processing in the main storage device, and a business program can be executed independently without being affected by copy processing. To provide a simple copy processing method.

[0004]

In order to achieve the above object, the copy processing method of the present invention provides a first duplication setting in a computer system having a duplication volume mechanism.
Of the data transfer buffer (4) for controlling the first and second external storage devices in the input / output control device (3) that connects the external storage device (1) and the second external storage device (2). )
When the input / output start instruction from the business program (6) is received during the copy processing between the first and second external storage devices, the instruction is preferentially processed. If not, the read and write processes for copying are separately performed via the buffer (4) by the flag control, and if the input / output start instruction from the business program (6) is a write command, the data to be written is The feature is that when the data overlaps with the copy data, the duplicate data is transferred to the buffer (4).

[0005]

According to the present invention, the buffer already provided in the input / output control device is used to execute the copy processing in the input / output control device, and at the same time, the input / output activation command from the business program is executed by the flag control. Execute for copy processing. That is, when the input / output control device receives an input / output activation command from the business program, the input / output control device performs the process. If there is no input / output start instruction from the business program, the copy control is partially performed via the buffer in the input / output control device by the flag control, and the input / output start instruction is received again. As described above, it is not necessary to secure a buffer for copy processing in the main storage device, and the copy processing can be performed by giving priority to the input / output start instruction from the business program. As a result, the copying process can be executed only within the input / output control device, so that the usage efficiency of the computer system can be improved. Further, when the input / output activation command is a write command, it is determined whether or not it is duplicated with the copy data, and the data being copied is transferred to the buffer. Can be consistent.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a functional block diagram of a computer system to which a copy processing method according to an embodiment of the present invention is applied, and is a schematic diagram of copy processing and read / write processing during the copy processing. In FIG. 1, reference numeral 1 is a first magnetic disk device that is a current working, 2 is a second magnetic disk device that is a spare, and both magnetic disk devices 1 and 2 are assumed to be duplicated. Reference numeral 3 denotes an input / output control device that controls the magnetic disk devices 1 and 4, reference numeral 4 denotes a buffer included in the input / output control device 3, and reference numeral 5 denotes a copy processing unit implemented by firmware in the input / output control device 3. 6 is a business program. In the present embodiment, two flags, a copy mode flag and a read / write flag, are prepared in the control table in the copy processing unit 5 of the magnetic disk control device 3 so that the business program 6, that is, the upper processor, transfers data to the magnetic disk device. When an input / output activation command for activating read / write or other input / output device is received, the input / output processing is performed. On the other hand, when there is no input / output activation command from the business program 6, the copy mode flag 10 is turned on, and the read / write flag 11 is turned on or off in accordance with read or write, and the buffer in the magnetic disk controller 3 By ensuring the number 4, the copy process is partially performed, and when the copy process is completed, the copy mode flag is turned off and the input / output start command is accepted again.

FIG. 2 is a diagram of a control table in the copy processing unit according to the present invention. In FIG. 2, 10 is a copy mode flag indicating the copy mode, 11 is a read / write flag indicating the processing content of the next copy processing, and 12 is a logical block of the magnetic disk device up to the copy end portion during the copy processing. It is a transferred block address which is indicated by an address and saved. The copy mode flag 10 has "01" and "10", of which "01" is a flag indicating that a copy process is being performed from the first magnetic disk device 1 to the second magnetic disk device 2. Yes, '10' is the second
This is a flag indicating that the copying process from the magnetic disk device 2 to the first magnetic disk device 1 is being performed. Further, the read / write flag 11 has "0" and "1", of which "0" is a flag indicating the read mode,
"1" is a flag indicating the write mode.

FIG. 3 is a block diagram of a buffer used in the present invention. In FIG. 3, reference numeral 20 is a data transfer buffer for processing a read / write command by an input / output activation instruction from the business program 6, and 21 is a copy processing buffer according to the present invention. The input / output activation command from the business program 6 instructs the magnetic disk device and other input / output devices to perform processing such as read / write.
In this case, the data transfer buffer 20 is a relay point for transferring the data read from the input / output device to the processor when reading, and a relay point for writing the data transferred from the processor to the input / output device when writing. Becomes On the other hand, in the copy command from the copy processing unit 5, a read command and a command execution to the magnetic disk device 1 are instructed to the copy processing buffer 21 and then a write command to the magnetic disk device 2 is continuously instructed. To be done.

FIG. 4 is an operation flowchart of the copying process showing an embodiment of the present invention. The business program 6 has a copy source magnetic disk device number and a copy destination magnetic disk device number as information. Now, the copy source magnetic disk device is DKU1 and the copy destination magnetic disk device is DKU2.
And First, when a command instructing copy processing is issued by the business program 6 (step 102), '01' is set in the copy mode flag 10 in the copy processing section 5 indicating that copy processing is in progress. Set '0
1'designates copying of data from DKU1 to DKU2. Conversely, when copying data from DKU2 to DKU1, '10' is set in the copy mode flag 10. Furthermore, a flag 1 indicating the content of the next copy process
'0' is set to 1 and '000' is set to the transferred block address 12 for saving the progress of the copying process.
The copying process is started by setting 00000 '. Note that "0" is the read mode and "1" is the write mode. When executing a command for instructing copy processing, the buffer 4 in the magnetic disk controller 3 is divided into a data transfer buffer 20 and a copy processing buffer 21 for use.

On the other hand, when a command such as read / write is issued from the business program 6 during the copying process (step 100), the input / output activation command of the command is retrieved,
Command processing is executed (step 101). This time,
If a write command is issued, the I / O controller writes the data to both DKU1 and DKU2 to ensure the data identity of DKU1 and DKU2. After the command processing is completed, the process returns to the command reception processing (step 100) again, the input / output start instruction is received, and the input / output start instruction is always processed with priority. Here, if no command is issued from the business program 6,
If the copy mode flag 10 is set to "01" or "10", the read / write flag 11 is referred to (step 1).
03), if the flag 11 is "0", the copy data of the copy source magnetic disk device is read (step 104), and if the flag 11 is "1", the copy data is written to the copy destination magnetic disk device. (Step 105). At the time of reading, an appropriate amount of data in terms of system performance is read from the copy source magnetic disk unit DKU1, the data is stored in the copy processing buffer 21, and at the same time the read / write flag 11 in the control table is set to "0" (read mode).
From "1" (write mode) to step 1
00.

FIG. 5 shows the command processing (10
It is a detailed flowchart of 1). When a read command is issued from the business program 6 at the time of returning to step 100 (step 200), the read command process is executed (step 201), but this process is executed via the data transfer buffer 20. Therefore, the data read in step 104 of FIG. 4 is not lost. When the read / write flag 11 is set to "1" (write mode) during the copying process and the write command is issued again (step 200), the copy mode flag 10 is checked (step 200). 202),
If it is not the copy mode, the write command process is executed (step 206), and after the end, the process proceeds to step 100 of FIG. On the other hand, if it is the copy mode (step 20)
2) The read / write flag 11 is checked, and if the flag 11 is "0" (read mode), the write command processing is executed as it is (step 206). Also, the read / write flag 11 during the copying process is "1".
If it is (write mode) (step 203), the block address of the data already read in the copy processing buffer 21 by the transferred block address 12 and this write command activation information, that is, the logical block on the magnetic disk device. Check the address (step 204). As a result of judging whether there are overlapping parts,
If there is an overlap in the block address of the read data (step 204), the transfer data by the write command is transferred to the copy processing buffer 21 (step 205), and then the write command processing is executed (step 206). . If there is no overlapping part in the block address of the read data (step 204), the write command process is executed as it is (step 206).
By the above processing, even if the write command is issued from the business program 6 during the copy processing, the data consistency of DKU1 and DKU2 is guaranteed.

Returning to FIG. 4, at step 105, the data read at step 104 is written to the copy destination magnetic disk unit DKU2, and the read / write flag 11 is changed from "1" (write mode) to "0" ( Rewrite to read mode). Next, in step 105, the block addresses up to the copied portion are saved in the transferred block address 12. That is, the transferred block address is updated (step 106).
Next, the transferred block address 12 is compared with the maximum block address of the DKU to determine whether or not the copying process is completed (step 107). If the copying process has been completed, the flag 12 is set to "0" to cancel the copying mode.
0'is set (step 108). On the other hand, if the copying process is not completed (step 107), step 1
The process returns to 00 and waits for the command issued by the business program 6. If the command has not been issued, steps 102 to 108 are repeated. In this way, the process from the business program 6 can be preferentially executed, and the copy process can be efficiently executed only in the input / output device.

[0013]

As described above, according to the present invention,
It is not necessary to provide a complicated copy processing unit or buffer in the OS level upper program, the copy processing is performed only within the input / output device, and the input / output start command from the business program is prioritized. It can be executed without being affected by the above, and efficient copy processing can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an input / output system to which a copy processing method of the present invention is applied.

FIG. 2 is a diagram showing the contents of a control table in the copy processing unit in FIG.

3 is a diagram showing the contents of a buffer in the magnetic disk control device in FIG.

FIG. 4 is a schematic operation flowchart of a copy processing method according to an embodiment of the present invention.

5 is a detailed flowchart of command processing in FIG.

[Explanation of symbols]

 1 1st magnetic disk unit 2 2nd magnetic disk unit 3 magnetic disk controller 4 buffer 5 copy processing unit 6 business program 10 copy mode flag 11 read / write flag 12 transferred block address 20 data transfer buffer 21 copy processing buffer

Claims (1)

[Claims] 1. In a computer system having a redundant volume mechanism, the first and second external devices are provided in an input / output control device that connects a first external storage device and a second external storage device, which are set to be redundant. A data transfer buffer for controlling the storage device is provided, and when an input / output activation command from the business program is accepted during the copying process between the first and second external storage devices, the command is given priority. If there is no input / output start instruction, read and write processing for copying are separately performed via the buffer by the flag control, and the input / output start instruction from the business program is a write command. In this case, when the data to be written overlaps the copy data, the duplicate data is transferred to the buffer.