JPH01196646A - Memory back-up system - Google Patents

Abstract

PURPOSE:To easily hand over information on a memory even when there is system interruption by deciding whether keeping operation is interrupted or not according to the matching of information for confirmation, which are added to the head and end of keeping information, and restoring the information from a newest keeping area, for which keeping is completed, on the basis of defining information. CONSTITUTION:The defining information to define correspondence relation between a back-up subject range (zone) 4 of a memory 1 and a keeping destination area 5 of plural external storages 2 are opened in a zone defining information area 3 on the memory at an arbitrary time point and kept in the respective external storages 2. When a system goes down, these kept defining information are restored on the memory 1 when the system is re-started. On the other hand, in each check point (zone defining area address), the information in the zone 4 are stored in the plural external storages 2 according to the defining information by adding the information for writing completion confirmation to the head and end of the keeping information. Thus, even when there is the system interruption, the information on the memory can be easily handed over.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a memory backup method in which information in the memory of a computer system is saved in external storage and restored when the system is restarted after interruption.

[Conventional technology]

In information processing systems that require high reliability, in order to speed up the process of restarting services in the event of a computer failure, information in main memory and other areas is constantly saved to secondary storage such as a magnetic disk. Sometimes a spare computer loads this information into memory and resumes service. Conventionally, this memory evacuation and recovery processing has been implemented individually by a management program for each piece of information.

[Problem to be solved by the invention]

In the conventional method, the management program must individually perform the process of saving and restoring information such as the main memory for each piece of information, making it difficult to achieve high reliability and resulting in duplicate program development. There were other problems. Furthermore, it is difficult to implement processing to save only updated information, and more information is saved than necessary.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a memory backup method that can easily take over information in memory even if the system is interrupted.

[Means to solve the problem]

In order to achieve the above object, in the memory buffer block method of the present invention, when multiple external memories are used as storage areas, the correspondence between the memory backup target range (hereinafter referred to as zone) and the storage area is If you want to generate definition information that defines relationships and save it in each external memory, and then save the information in the memory to the external memory, the information in the zone can be saved to multiple external memories based on the definition information. If you want to add write completion confirmation information to the beginning and end of the save information to the area so that all of the multiple save destination areas are not being updated at the same time, and then restore it to memory,
It is determined whether the save operation has been interrupted by comparing the confirmation information added at the beginning and end of the save information, and the save operation is restored to the memory based on the definition information from the latest save area where the save has been completed. .

In addition, if a zone is composed of multiple pages, each page has an update bit, and information in memory is saved to external storage, the updated page in the rezone is selected by checking the update bit, and the selected Serially save the pages created in multiple external storage storage areas.

Furthermore, when saving information in the memory to external storage, storage areas of a plurality of external storages are switched and used cyclically for each storage process.

[For production]

Definition information that defines the correspondence between the backup target range (zone) of the memory and the storage destination areas of a plurality of external memories is opened in the zone definition information area on the memory at any time and is also saved in each external storage. When the system goes down, this saved definition information is restored to memory when the system is restarted.

On the other hand, for each checkpoint (zone domain address), information in the zone is stored in a plurality of external memories, with write completion confirmation information added to the beginning and end of the stored information, according to the definition information. At this time, the zone is made up of multiple pages, and by checking the update bit corresponding to each page, you can select the updated page and save it to multiple external memories, or you can save it to multiple external memories for each save process. Switch the storage area and use it cyclically. When restoring the saved information to the memory, it is also restored according to the definition information that has already been restored.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an embodiment of the present invention, and shows the relationship between zones to be backed up on memory and a storage area (backup area) on external storage. Note that in this embodiment, two external memories are used as storage areas.

In Figure 1, 1 is the main memory, 2 is the external memory, 3 is the zone definition information area, 4 is the backup target range (zone),
5 indicates a backup area.

Zone 4 on main memory 1 corresponds to backup area 5 on external memory 2. These correspondences are managed by the zone definition information in the zone definition information area 3. 6 and 7 are information for checking completion of writing. Here, the check information at the beginning and end of the backup area 5 is used not to define the spatial arrangement but only to define the update order.

FIG. 2(a) shows an example of the configuration of zone definition information.

The zone identifiers (I, D) are internal names in the system that are managed by the user to avoid duplication.

The zone start address (X) is the start address of zone 4 on the main memory 1, and the zone size (W) is its size. Each backup area access information is an address of the backup area 5 on the external storage 2. FIG. 2(b) shows an example of backup device definition information.

FIG. 3 shows the process of creating zone definition information in the zone definition information area 3 and saving it in the external storage 2. This is accomplished by executing zone definition/open window commands. The parameters of this command include a zone identifier (ID), a zone start address (X), a zone size (W), and return information (R) indicating the address of the zone definition information area 3.

In FIG. 3, steps 12 and 13 are a zone determination process, and step 14 is a zone definition area securing process. Steps 15 to 18 show the process of cutting out the backup area 5 from each external storage 2 and registering the backup area access information in the definition information. This may be done by securing a storage light area in advance and only making the correspondence. Note that α is the validity check data area size of 6 and 7. Step 19 shows a process of writing the established definition information to the external storage 2.

This can be easily achieved by defining a zone using fixed definition information developed in memory during initial settings and using this zone.

This step saves the zone definition information, and by restoring this zone definition information when the system restarts,
It becomes possible to restore information in other general zones even after system interruption.

FIG. 4 shows a process when zone 4 on main memory 1 is stored serially in each external memory 2. Note that this is an embodiment in which the zone 4 is composed of a group of pages, each page is provided with an update bit, and a page with an update is selected by checking the update bit, and the page is saved.

In FIG. 4, step 21 is a process of extracting updated pages from pages within a designated zone based on zone definition information, which can be easily realized in a computer equipped with a virtual space function. At this time, only this process is controlled to reset the update history display of the page to which the zone belongs. Step 22 is a data creation process for detecting interruption of the update process, which uses a timer value or the like to avoid coincidence with the previous data. Steps 24 to 26 are processing for writing updated pages to the backup area. That is, if the update is not completed due to system judgment or the like, step 26 will not be completed, so the check data 6.7 will be inconsistent, and it can be determined that an interruption has occurred. In addition to the method of providing check data for each zone, there is also a method of providing the data for each page or the like. Steps 23, 27, and 28 are processes for sequentially writing to each backup area 5 of a plurality of external storages 2.

In FIG. 4, only updated pages in zone 4 are written to the external storage, so the processing time can be shortened.

FIG. 5 shows another embodiment in which zone 4 on main memory 1 is stored in each external memory 2. In FIG. This writes the entire specified zone to the external storage 2, but uses the external storage 2 cyclically to perform one update process on one of M (M≧2) external storage devices. This prevents a decline in update performance. That is, in steps 30, 32, and 33, the external storage 2 is used cyclically. If the update is interrupted, the 4th
As in the figure, an abnormality is detected and the zone is restored using information from the device used one time ago. Of course, there is also a method of updating multiple devices at a time, taking into account device failures.

This can be easily achieved by adding attribute parameters.

Furthermore, it is also possible to easily mix the two methods shown in FIG. 4 and FIG. 5 by adding attribute parameters to the zone definition.

FIG. 6 shows the restoration process. Here, steps 12 and 13 show processing for cases in which the memory range (zone) is set to the same address as before the interruption and to an arbitrary address. Step 40 is a process of searching the zone definition information area 3 and extracting the zone definition information of the specified ID. Step 41 is a process of comparing the check start information 6 and the check end information 7 to confirm the completion of writing, and This is a process of determining the external storage 2 for restoration by determining the latest value (latest time, etc.) of the relevant data.

Step 42 is a zone data restoration process. Note that the restoration of the zone domain 3 can be performed in the same manner if the domain zones are written and retained in the same format.

Although one embodiment of the present invention has been described above, it goes without saying that it is also easy to add a zone release command for specifying a zone and releasing a backup area. Also, if the external storage device is a magnetic disk shared between systems,
Using this magnetic disk, it is possible to restore information using another computer, and by using a semiconductor storage device, high-speed information restoration can be easily achieved.Furthermore, expanded storage allows for synchronous access similar to main memory. By using , processing switching and waiting for switching associated with multiprocessing can be eliminated, and high performance (
High output/high response) and high reliability zones can be easily realized.

〔Effect of the invention〕

As explained above, according to the present invention, even if there is a system interruption, the information on the memory can be easily taken over, so there are the following advantages.

(2) There is no need to create a unique recording process using external storage, and the memory can be used as a recording medium that can store information like external storage.

■ Target any range of memory for backup (zone)
In addition, the timing of backup can be set freely for each zone, so multiple programs can easily construct their own down recovery simply by ensuring that zone identifiers (IDs) do not overlap.

■ Even if a system interruption occurs during the update process, the zone is restored with complete and consistent information that has been backed up, so the restart point for the process is clear and the information correction process is simple.

■ Good backup performance because the redundancy of information on external storage is used to reduce write operations.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between zones and backup areas in an embodiment of the present invention, FIG. 2 is a diagram showing an example of zone definition information and backup device definition information, and FIG. 3 is a diagram showing the establishment and backup area of zone definition information. FIGS. 4 and 5 are process flow diagrams for saving a zone, and FIG. 6 is a process flow diagram for restoring a zone. 1... Main storage device, 2... External storage device, 3...
-Zone definition information area, 4...Zone, 5...Backup area, 6...Start information for checking, 7...Last information for checking. Figure 1 Figure 2 (α) (g) GI2I

Claims (3)

[Claims] (1) In a memory backup method that saves information in the computer system's memory to external storage and restores it to memory when the system is restarted, multiple external storage areas are used as storage areas, and the memory backup target range ( If you want to generate definition information that defines the correspondence between a zone (hereinafter referred to as a zone) and a storage area and save it in each external memory, and save information in the memory to an external memory, the zone will be created based on the definition information. information in the storage area of a plurality of external storages, adding writing completion confirmation information to the beginning and end of the storage information so that all of the plurality of storage areas are not in the process of updating at the same time, When restoring to memory, it is determined whether the saving operation was interrupted by comparing the confirmation information added at the beginning and end of the saved information, and the definition is restored from the latest saving area where saving is completed. A memory backup method characterized by restoring information to memory. (2) When a zone is composed of multiple pages, each page has an update bit, and the information in the memory is saved to external storage, the updated page in the zone is selected by checking the update bit, and the selected page is selected. 2. The memory backup method according to claim 1, wherein the stored pages are serially stored in storage destination areas of a plurality of external memories. (3) Memory backup according to claim (1), characterized in that when saving information in the memory to external storage, storage destination areas of a plurality of external storages are switched and used cyclically for each storage process. method.