JPH0362244A - Data assurance control system for external semiconductor memory device - Google Patents

Abstract

PURPOSE:To switch a composite system to a high speed system by restoring the undefined data based on the transfer data saved into an external nonvolatile memory medium when it is detected that the transfer data obtained from the preceding access is turned into the undefined data due to a fault. CONSTITUTION:When the recovery control data 14 is checked to know that the transfer data obtained from the preceding access is turned into the unfixed data due to a fault, the present access request is interrupted and the undefined data received from a data saving area 15 is restored. Then the process is restarted to the present access. These data ending properties are automatically secured by a data ending property securing mechanism 12 and therefore the processing load is extremely reduced for an access requester 20 especially in a composite system, etc. Thus it is possible to allocate the important control data, etc., to an external semiconductor memory device 10 and to easily use these allocated data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a data guarantee control method in a semiconductor external storage device for restoring undefined data when data being transferred to the semiconductor external storage device becomes undefined data due to a failure.

Detects undefined data on a semiconductor external storage device.

The purpose is to provide a means of automatic recovery.

A write processing means that saves data to be transferred to the semiconductor external storage device onto an external nonvolatile storage medium and sets recovery information regarding the transferred data on the external nonvolatile storage medium, and write or read access to the semiconductor external storage device. When processing a request, the recovery information set in the external non-volatile storage medium is referenced, and if it is detected that the data transferred by the previous access has become undefined data due to a failure, the transferred data is saved to the external non-volatile storage medium. and a recovery processing means for restoring indefinite data based on the above.

[Industrial application field]

The present invention relates to a data guarantee control method in a semiconductor external storage device for restoring undefined data when data being transferred to the semiconductor external storage device becomes undefined data due to a failure.

A system in which multiple computers are connected through communication channels is called a composite system.The computers that make up the composite system are
Here it is called a cluster.

In such a complex system, it is effective to use a semiconductor storage device as an external storage medium in order to process a large amount of transactions. An external storage medium that uses semiconductors and is capable of high-speed input/output is called a semiconductor external storage device.

The integrity of data transferred to a semiconductor external storage device may not be guaranteed due to a hardware failure (for example, a CPU failure) in one system.

It is desirable to be able to guarantee the integrity of such transferred data.

[Conventional technology]

FIG. 9 is a diagram for explaining an example of a conventional data transfer method.

The data being transferred to the storage device may not be the value it was before the transfer due to a hardware failure in the main body such as a CPU@damage.
The value may not even be the value after transfer. Such data whose completeness is not guaranteed is called indeterminate data.

Conventionally, in order to detect this undefined data, check bytes are placed before and after the data section to be transferred, as shown in FIG. Set the same value, such as a sequence number or a timestamp, in the check bytes before and after the data part, and transfer the data.
If the values of the check bytes around 9 are different when the data is read, it is determined that the data has become undefined due to a failure.

[Problem to be solved by the invention]

In the data transfer method using check bytes as shown in FIG. 9, it is possible to determine whether or not the data transfer is completed, but it is not possible to guarantee the completeness of the transfer delay.

For example, as shown in FIG. 10, assume that cluster #1 is writing record a to the semiconductor external storage device IO. While transferring the data for record a, cluster #1 encountered a failure.

If a crash occurs, the data written to the semiconductor external storage device 10 will have different contents from the contents of record a and the contents of the original 9, such as record a'.

If this record a'' is read by cluster #2, it is possible to detect that record a' is unspecified data by checking the check bytes as shown in Figure 9, but the correct contents of record a or the original completed contents can be detected. cannot be obtained.

Therefore, conventionally, there has been a problem in that it is not possible to store control data and the like that are frequently used by each cluster on the semiconductor external storage device 10.

In other words, if the control data (for example, inter-cluster exclusion information, etc.) placed on the semiconductor external storage device IO becomes undefined, the operation of the complex system after referencing the undefined data is not guaranteed. Control data could not be placed on the storage device 10.

The present invention aims to solve the above-mentioned problems, and by providing a means for detecting and automatically restoring undefined data on a semiconductor external storage device, the present invention can provide a means for detecting and automatically restoring undefined data on a semiconductor external storage device, without imposing a burden on the access request source.
The purpose is to make data with guaranteed completeness available.

[Means to solve the problem]

FIG. 1 shows an example of the configuration of the present invention.

In FIG. 1, 10 is a semiconductor external storage device.

11 is a computer main body consisting of a CPU, memory, etc.;
2 is a data integrity guarantee mechanism; 13 is a data storage unit in which user data etc. are stored; 14 is recovery control data having information such as whether data integrity guarantee processing is necessary; 1;
5 is a data save area for saving data transferred to the data storage unit 13; 16 is a write processing unit that processes access for write requests; 17 is a read processing unit for processing access for read requests; and 18 is a recovery for undefined data. 19 is a transfer buffer for transferring data to the data storage unit 13, and 20 is a source requesting access to the semiconductor external storage device 10.

When the access request source 20 accesses the semiconductor external storage device IO, the access requester 20 uses a macro interface or the like to
An access request is issued to the data integrity assurance mechanism 12.

Write processing section 16 in data integrity assurance mechanism 12
for write access requests.

The data transferred to the semiconductor external storage device 1σ is saved in the data save area 15, and recovery information such as a transfer completion indication, transfer address, and transfer data length regarding the transferred data is set in the recovery control data 14. Thereafter, the transfer data set in the transfer buffer 19 is written to the requested data storage section 13.

In this example, the semiconductor external storage device 10 is the computer main body 1
The semiconductor external storage device 10 is a nonvolatile storage device that is not affected by the state of the semiconductor external storage device 10, and includes not only a data storage section 13 but also a storage area for recovery control data 14 and a data save area 15.

The data integrity check by the data integrity guarantee mechanism 12 is performed when there is any access request to the primary data storage unit 13.

In processing a write or read access request to the semiconductor external storage device 10, the write processing unit 16
Or ``The reading processing unit 17 reads the recovery control data 1
Refer to the recovery information set in 4 and check whether the data transferred by the previous access has become undefined data due to a failure.

If it is detected that the data is indefinite, the recovery processing unit 18 is activated.

The recovery processing unit 18 stores the transferred data related to the previous access, which has been saved in the data saving area 15 of the semiconductor external storage device tto, which is an external nonvolatile storage medium, at the corresponding location in the data storage unit 13. By writing in
Perform recovery of undefined data.

[Effect]

In the present invention, access to the semiconductor external storage device 10 is
Focusing on the fact that it is much faster than a magnetic disk device or other external storage devices that involve mechanical operations, the data transferred to the data storage unit 13 is saved in advance in the data save area 15. . And data storage unit 1
A transfer completion display indicating whether data transfer for 3 is completed or not.

The transfer address, transfer data length, etc. in the data storage unit 13 are set as recovery control data 14.

The completeness of the data related to the previous access is checked by referring to the recovery control data 14 when a write or read access request is made to the data storage unit 13. The address of the data storage unit 13 at this time does not need to be the same between the previous access and the current access.

If the recovery control data 14 is inspected and it is found that the transferred data related to the previous access has become undefined data due to m damage, the current access request is interrupted and data is transferred from the data save area 15. , and then resumes processing for the current access request.

These data integrity guarantees are Data Integrity Guarantee 11
1ti12 automatically, the processing burden on the access request source 20 is significantly reduced, especially in complex systems. Along with this.

Important control data and the like can be easily placed and used in the semiconductor external storage bag W, 10.

〔Example〕

FIG. 2 is an example of a system to which the present invention is applied, and FIG. 3 is an explanatory diagram of a transfer completion display area used in the embodiment of the present invention.

Fig. 4 is a configuration diagram of an embodiment of the present invention, Fig. 5 is an example of the format of a parameter packet according to an embodiment of the present invention, Fig. 6 is a processing flow when writing by the data integrity guarantee mechanism, and Fig. 7 is FIG. 8 shows a processing flow when reading data by the data integrity guarantee mechanism. FIG. 8 shows a process flow of recovery processing by the data integrity guarantee mechanism.

The present invention can be applied to a complex system as shown in FIG. 2, for example.

The semiconductor external storage device 10 is a nonvolatile external storage device that can be shared between clusters. This semiconductor external storage device 110 includes a memory section 30 corresponding to the data storage section 13 shown in FIG. 1, and a recovery control data 14.
It has a transfer data logging area 31 in which a data save area 15 and the like are provided.

Each computer main body 11A, IIB has a CPU 33 and a locally used memory section 35, and can access the semiconductor external storage device 10 via a memory control unit (MCU) 32. It also has a transfer data save area 34 corresponding to the transfer buffer 19 shown in FIG.

In the storage area of the recovery control data 14 shown in FIG.
A transfer completion display area as shown in the figure is provided. The transfer completion display area consists of status display areas Sl and S2, and is used to detect undefined data.

This is used as follows. Semiconductor external storage device 10
When transferring data, first the status display area S1
``Transferring'' is written in ``Transferring'' first, and then ``Transferring'' is written in the status display area S2. When the data transfer is completed, write “Transfer Complete” in the status display area S1 and then write the status display area S1.
Write “transfer complete” to 2.

If both the status display area S1 and the status display area S2 indicate "transfer complete", it is determined that the data integrity guarantee process is unnecessary because the data transfer has been completed.

If either the status display area S1 or the status display area S2 is "transferring", it is determined that data integrity guarantee processing is necessary because data transfer has been interrupted.

As mentioned above, the reason why the transfer completion display is displayed in both the status display area SL and the status display area S2 is because the transfer completion display itself is indefinite data and the data transfer is interrupted. This is to prevent the possibility of misunderstanding whether the data transfer has been completed.

Next, the present invention will be explained in detail with reference to FIG. Fourth
In the figure, the same symbols as in Fig. 1 are shown.

Corresponding to what is shown in FIG. 1, 40 is a recovery work area for temporarily saving the currently transferred data during recovery processing, 41 is a recovery II i'B buffer for reading recovery control data 14, 42 is an access request parameter packet, 43 is a database management subsystem, 44 is an application program, and 45 is an application program 4.
4 represents the record area to be used, and 46 represents the page buffer.

In response to a write request from the application program 44 to the data storage unit 13, the database management subsystem 43 issues an access command to the data integrity guarantee mechanism 12. Furthermore, in response to a read request, the database management subsystem 43 issues an access command provided by the data integrity guarantee mechanism 12.

When writing data to the data storage section 13 of the semiconductor external storage device f10, the data integrity guarantee mechanism 12 first copies the data in the page buffer 146 to the transfer buffer 19. Before transferring the data to the data storage unit 13, the recovery control data 14 in the semiconductor external storage device 10 is read into the recovery control buffer 41, and it is determined whether data integrity guarantee is necessary.

If necessary, the following processing is performed. First, the contents of the transfer buffer 19 are written to the recovery work area 40. And the contents of the data save area 15.

Read into the transfer buffer 19. Then, the transfer address and transfer data length are determined from the previously read contents of the recovery control buffer 41, and the data in the transfer buffer 19 is written into the data storage section 13 again. This recovers the indefinite data. After that, recovery work area 4
0 data.

The data is read into the transfer buffer 19 and the interrupted data transfer process is restarted.

When reading data from the semiconductor external storage device 10, the recovery control data 14 is read into the recovery control buffer 41 before transferring the data in the data storage section 13 to the transfer buffer 19.

Determine whether data integrity assurance processing is necessary.

Secondary processing is performed if necessary. First, the contents of the data save area 15 are read into the transfer buffer 19. Since the transfer address and transfer data length are known from the contents of the recovery control buffer 41 that were previously read, the data in the transfer buffer 19 is read.

This causes the data to be written to the data storage unit 13 again.

Recover the undefined data related to the previous access. After that, the data reading process is resumed.

In this embodiment, the interface between the data integrity guarantee mechanism 12 and the access request source is a macro interface for write macro instructions and read macro instructions.

This write and read macro instruction.

Two types are available: record specification and address specification. A parameter packet as shown in FIG. 5 is specified as a parameter of the macro instruction.

FIG. 5(a) shows the format of a parameter packet in the case of record specification, in which the number of records and record number are specified. In addition, the number of buffers and the buffer address are specified accordingly.

FIG. 5(b) shows a parameter packet format for address specification, in which the transfer length (transfer data length) and the address of the transfer data are specified. Also, in response to this,
Specify the buffer address.

When the application program 44 shown in FIG. 4 updates the record in the page buffer 46 with an update command and issues a write request to the data storage section 13 of the semiconductor external storage device 10, the data pace management subsystem 43 performs data integrity processing. Issue a write macro command to the guarantee mechanism 12.

As a result, the data integrity guarantee mechanism 12 executes the access process shown in FIG. 6. ■～■ in the following explanation
corresponds to processes ① to ② shown in FIG.

■ Read the transfer address, transfer data length, and page buffer contents of the data requested to be transferred.

■Recovery control data for semiconductor external storage devices.

Load into main memory.

■ Determine whether data integrity guarantee processing is necessary based on the read recovery control data. That is,
Determine whether the transfer completion display indicates "Complete". When “Complete” is not indicated, the previous transfer data is
Since the data is undefined, process (■) is executed. If it is “completed”, move on to process ■.

■ Recover undefined data using the recovery process described later.

(2) Copy the contents of the main memory transfer buffer to the data retirement area of the semiconductor external storage device.

■ Set the transfer address and transfer data length of the data to be transferred.
Write to the recovery control data of the semiconductor external storage device.

■ Display the start of data transfer, that is, write "transferring" in the recovery control data transfer completion display.

(2) Transfer the contents of the transfer buffer to the data storage section of the semiconductor external storage device.

■ Write the transfer completion indication to the recovery control data and write “
“Complete” and then return control to the database management subsystem.

When the application program 44 shown in FIG. Issue.

As a result, the data integrity guarantee mechanism 12 executes the access process shown in FIG. 7. ■～■ in the following explanation
corresponds to processes ① to ② shown in FIG.

■ Read the transfer address and transfer data length of the data requested to be transferred into the main memory.

■Recovery control data for semiconductor external storage devices.

Load into main memory.

■ Determine whether data integrity guarantee processing is necessary based on the read recovery control data. That is,
Determine whether the transfer completion display indicates "Complete". If it is not "Complete", the previously transferred data is indefinite data.

Execute process ■. If it is “Completed”.

Move on to processing ■.

■ Recover undefined data using the recovery process described later.

(2) Transfer the data in the data storage section of the semiconductor external storage device to the transfer buffer.

■ Copy the contents of the transfer buffer to the page buffer,
Return control to the database management subsystem.

In the processing shown in FIGS. 6 and 7, if data integrity guarantee processing is required, the current access processing is interrupted,
The following processes 1 to 2 shown in FIG. 8 are executed.

■ Copy the contents of the transfer buffer to the recovery work area.

■ Read the contents of the data save area where the previously transferred data is saved into the transfer buffer of the main memory.

■ Data in the transfer buffer based on the recovery control data transfer address and transfer data length.

Undefined data is recovered by rewriting it to the data storage unit.

■Write the transfer completion indication to the recovery control data.

■ Copy the data saved in the recovery work area to the transfer buffer. After that, 1 normal processing is resumed.

Note that the above-mentioned processes (1) and (2) may be omitted in the recovery process performed at the time of reading.

The data integrity assurance processing by the data integrity assurance mechanism 12 described above can be realized by software, but it is also possible to achieve even higher speed by implementing it using firmware or hardware mechanisms.

〔Effect of the invention〕

As explained above, according to the present invention, it becomes possible to eliminate undefined data on the semiconductor external storage device, so that the following effects can be obtained.

When the system goes down, it becomes possible to take over the information until after the system is restarted, and it becomes possible to place control data such as inter-cluster exclusive information in addition to the database on the semiconductor external storage device. This makes it possible to construct a true standby system capable of high-speed system switching in complex systems and the like.

[Brief explanation of drawings]

FIG. 1 shows a configuration example of the present invention. FIG. 2 shows an example of a system to which the present invention is applied. FIG. 3 is an explanatory diagram of a transfer completion display area used in the embodiment of the present invention. FIG. 4 is a configuration diagram of an embodiment of the present invention. FIG. 5 is an example of the format of a parameter packet according to an embodiment of the present invention. Figure 6 is the process flow when writing by the data integrity guarantee mechanism Figure 7 is the process flow when reading by the data integrity guarantee mechanism Figure 8 is the process flow of recovery processing by the data integrity guarantee mechanism Figure 9 is the conventional process flow FIG. 3 is a diagram for explaining an example of a data transfer method. FIG. 1O shows a diagram for explaining the problems of the prior art. In the figure, 10 is a semiconductor external storage device, 11 is a computer main body,
12 is a data integrity guarantee fi41. 13 is a data storage unit, 14 is recovery control data, 15 is a data save area, 1
Reference numeral 6 represents a write processing unit, 17 a read processing unit, 18 a recovery processing unit, 19 a transfer buffer, and 20 an access request source.

Claims (1)

[Claims] In a computer system equipped with a semiconductor external storage device, data transferred to the semiconductor external storage device is saved on an external nonvolatile storage medium, and recovery information regarding the transferred data is saved on the external nonvolatile storage medium. In processing a write or read access request to the semiconductor external storage device, a write processing means is configured to refer to the recovery information set in the external non-volatile storage medium, and the data transferred by the previous access is determined to be undefined data due to a failure. and recovery processing means for restoring undefined data based on the transferred data saved in the external non-volatile storage medium when it is detected that the external non-volatile storage medium is control method.