JP2007272493A - Computer system, data normality confirmation method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a defect in data normality confirmation processing in a server. <P>SOLUTION: A server 10 confirms data normality for data stored in a disk device 15 as object data. If a data normality confirmation event arises, the server 10 first clears cache data stored in a cache memory contained in a DIMM memory 11, then reads out data stored in the disk device 15 into the cache memory, and performs normality confirmation processing for the data stored in the cache memory. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a computer system, a data normality confirmation method, and a program thereof, and more particularly to a technique for confirming the normality of data stored in a disk device of a computer system.

In a computer system such as a server, the normality of data is confirmed, for example, whether or not the data stored in the disk device has been destroyed regularly or as necessary. When the data stored in the disk device is compressed data, the normality of the data is confirmed by a technique such as CRC. When the data is a backup file or the like, the normality can be confirmed by collation with the current data file in addition to the CRC method. A method for confirming data normality is described in Patent Document 1, for example.
JP-A-10-254785

  By the way, in recent computer systems, data received from the outside and data created in the computer system are usually stored in the cache memory at the same time as being stored in the disk device. In a computer system that is started and stopped on a daily basis, the cache data is erased each time the computer system is stopped. However, in a computer system used as a server in a server / client system, for example, cache data may be left for a relatively long period depending on the capacity of the cache memory and the operation frequency of the computer system. Such a computer system has the following problems.

  FIG. 4 is a block diagram schematically showing each processing step and data flow in order to explain this situation. In the figure, when a data update event for updating data occurs in the server 10 (step 1), the server 10 stores the data on the DIMM memory 11 constituting the main memory in the built-in cache memory ( Step 2) A process of writing data into the disk device 15 via the I / O-Bridge 13 and the SCSI interface 14 is performed by the process of the memory controller mounted on the North-Bridge 12. At this time, data destruction may occur in the processing of the I / O-Bridge 13 (step 3). In that case, abnormal data is generated (step 4), and the abnormal data is stored in the disk device. In this case, inconsistency occurs between the data stored in the cache memory and the data stored in the disk device 15.

  Thereafter, before the data stored in the cache memory is erased, for example, a regular normality confirmation event may occur. If this normality confirmation processing is normality confirmation of backup data, this normality confirmation is performed in the form of error correction using, for example, CRC error correction. When the computer detects that the necessary data is stored in the cache memory in the DIMM memory 11, the computer checks the normality with the backup data stored in the cache memory instead of the backup data stored in the disk device 15. Do. In this normality confirmation, no abnormal data is found and the process ends as “normality confirmation OK” (step 5).

  Thereafter, if an abnormality is found in the current data file and backup data is required, and the cache data is erased at that time, the backup data is read from the disk device 15. However, since the backup data stored in the disk device 15 has already become abnormal data at the time of writing, it is determined, for example, as abnormal data by CRC error correction. In such a case, both the current data file and the backup file cannot be used, and normal data does not exist.

  As described above, in the data normality check in the conventional server 10, the normality of the data generated / updated in the disk device 15 is confirmed because the data normality check is performed without explicitly clearing the cache data. The normality of cache data on the DIMM memory 11 may be confirmed instead of confirmation. For this reason, when data destruction or garbled data occurs via the I / O Bridge 13 or the like, even if the data on the disk device 15 is abnormal, the cache data on the DIMM memory 11 is normal, so there is an abnormality. The problem of being unable to detect was latent.

  In view of the above, the present invention provides a computer system in which normality confirmation is correctly performed by performing data normality confirmation processing in a correct procedure when normality confirmation is performed in a computer system having a cache memory. An object is to provide a data normality confirmation method and a program to be executed.

To achieve the above object, a computer system of the present invention is a computer system comprising a cache memory,
When a data normality confirmation event for checking data stored in the disk device occurs, at least a cache clear unit for clearing cache data corresponding to the data to be checked,
A data reading unit for reading the data to be confirmed from the disk device after the cache data is cleared by the cache clearing unit;
And a normality confirmation processing unit that performs normality confirmation of the data to be confirmed read from the disk device.

The data normality confirmation method of the present invention is a data normality confirmation method in a computer system including a cache memory,
When a data normality confirmation event occurs in which the computer checks data stored in a disk device, at least cache data corresponding to the data to be confirmed is cleared;
The computer, after the clearing step, reading the data to be confirmed from the disk device;
The computer includes a step of confirming normality of data to be confirmed read from the disk device.

Furthermore, the program of the present invention is a program for causing a computer system having a cache memory to execute data normality confirmation,
When a data normality confirmation event for checking data stored in the disk device occurs, at least clearing cache data corresponding to the data to be checked;
After the clearing step, reading the data to be confirmed from the disk device;
And confirming the normality of the data to be confirmed read from the disk device.

  According to the computer system, the data normality confirmation method, and the program of the present invention, when a data normality confirmation event occurs, the cache data is automatically cleared before actually proceeding to the data normality confirmation process. The data normality confirmation process is performed on the data stored in the disk device. Therefore, if there is an abnormality in the data stored in the disk device, the abnormality is detected, so that the malfunction that has occurred in the prior art does not occur and normality confirmation is performed correctly.

  In the computer system of the present invention, it is preferable that the data reading unit stores the data to be confirmed read from the magnetic disk device in the cache memory. In this case, the throughput of normality confirmation processing is improved.

  The target data for normality confirmation may be a backup file or any other data. In addition, the disk device that stores the target data for normality confirmation may be a disk device in the computer system or a disk device outside the system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram schematically showing data storage processing executed by a computer system according to an embodiment of the present invention. In the figure, a computer system (server) 10 includes a memory module (DIMM memory) 11, a North-Bridge 12, an I / O-Bridge 13, a SCSI interface 14, and a disk device 15, and has a general configuration as a server. .

  When a data update event occurs (step 1), the server 10 stores the data in the DIMM memory 11 in a cache memory built in the DIMM memory 11 (step 2). Next, the server 10 stores the data on the DIMM memory 11 in the disk device 15 (step 3). This data storage is executed by being written into the disk device 15 via the I / O-Bridge 13 and the SCSI interface 14 by the memory controller mounted on the North-Bridge 12.

  FIG. 2 is a schematic diagram similar to FIG. 1 showing the processing for checking the normality of the data written in FIG. The normality confirmation process starts with the occurrence of a normality confirmation event that designates CRC error correction, which occurs periodically, for example (step 1). The normality confirmation event is periodically issued according to data to be confirmed by using a system call, for example, by a dedicated application. When the normality confirmation event occurs, the server 10 first automatically clears the data in the cache memory by the cache clear processing unit (step 2). As a cache clear procedure, for example, a device control system call such as a system call ioctl in LINUIX / UNIX (registered trademark) is used to clear cache data in block device units defined on the disk device 15.

  Next, the server 10 reads necessary data from the disk device 15 and performs normal normality confirmation processing. In other words, since there is no cache data on the DIMM memory 11, normality confirmation target data is transferred from the disk device 15 via the SCSI interface 14, I / O-Bridge 13, and North-Bridge 12 by the data read processing unit. Are read out and newly cached on the DIMM memory 11 (step 3). The server 10 performs normality confirmation on the data on the disk device 15 by the normality confirmation processing unit (step 4). As a data normality confirmation method, a method using CRC error correction, parity error correction, error correction sum, or the like can be considered. Each processing unit is configured by a program stored in a storage device in the server 10.

  As described above, the data normality confirmation method according to the present invention is used to detect data abnormality on the disk device 15 due to data corruption that may occur in the I / O-Bridge 13 or the like. In this case, by confirming the normality of the data generated by the various data generation processes in the server 10, data corruption that occurs at the time of data transfer from the memory module (DIMM memory) 11 to the disk device 15 is detected. It automatically detects the presence of abnormal data.

  In the above-described embodiment, the server 10 can automatically detect the occurrence of a data abnormality that can be fatal automatically at an early stage. This solves the conventional problem that the failure cannot be detected even though the server 10 has a failure that greatly affects the service to be provided. In particular, when a data abnormality occurs in backup data or the like, the abnormality is detected only when an opportunity for actually requiring the backup data is encountered, and the necessity of the present invention is sufficiently high.

  In particular, when backup data is required, it is assumed that there is some abnormality in the current data. In such a case, if the backup data is destroyed, the data for guaranteeing the service is not stored in the system. The situation does not exist in any of the above, and the influence on the service is particularly great. Therefore, the present invention is particularly effective for checking the normality of backup data.

  In the description with reference to FIGS. 1 and 2, data writing on the disk device 15 in the server is taken as an example. However, the present invention can also be applied to data normality confirmation to an external disk device. An example of this is shown in FIG. This figure shows that the data normality confirmation method according to the present invention can be applied to data stored in an external disk device 17 connected via the SCSI interface 16. In the configuration shown in FIG. 3, processing similar to the processing described with reference to FIGS. 1 and 2 is performed on the data stored in the external disk device 17 except that data normality confirmation processing is performed. It shows that.

  Although the present invention has been described based on the preferred embodiments, the computer system, the data normality confirmation method, and the program of the present invention are not limited only to the configuration of the above embodiments, Those in which various modifications and changes have been made to the configuration are also included in the scope of the present invention.

The block diagram which shows typically the data preservation | save process in the server which concerns on one Embodiment of this invention. The block diagram which shows typically the data normality confirmation process in the server of FIG. The block diagram which shows the data normality confirmation process in the server which concerns on the modification of this invention. The block diagram which shows typically the data normality confirmation process in the conventional server.

Explanation of symbols

10: Server 11: DIMM memory 12: North-Bridge
13: I / O-Bridge
14, 16: SCSI interface 15, 17: Disk device

Claims (6)

A computer system comprising a cache memory,
When a data normality confirmation event for checking data stored in the disk device occurs, at least a cache clear unit for clearing cache data corresponding to the data to be checked,
A data reading unit for reading the data to be confirmed from the disk device after the cache data is cleared by the cache clearing unit;
A computer system comprising: a normality confirmation processing unit that executes normality confirmation of data to be confirmed read from the disk device.   The computer system according to claim 1, wherein the data reading unit stores data to be confirmed read from the magnetic disk device in the cache memory.   The computer system according to claim 1, wherein the data to be confirmed is a backup file.   The computer system according to claim 1, wherein the disk device is an external storage device disposed outside the computer system. A data normality confirmation method in a computer having a cache memory,
When a data normality confirmation event occurs in which the computer checks data stored in a disk device, at least cache data corresponding to the data to be confirmed is cleared;
The computer, after the clearing step, reading the data to be confirmed from the disk device;
And a step of confirming normality of data to be confirmed read from the disk device by the computer. A program for causing a computer system having a cache memory to execute data normality checking, wherein the computer
When a data normality confirmation event for checking data stored in the disk device occurs, at least clearing cache data corresponding to the data to be checked;
After the clearing step, reading the data to be confirmed from the disk device;
And executing the step of confirming the normality of the data to be confirmed read from the disk device.

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