JP2704137B2 - Current / spare switching method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working / standby switching system in a loosely coupled multiplex system composed of a plurality of hosts, and more particularly to a working system in a system having a plurality of standby hosts for one active host. -Regarding the pre-switching method.

[0002]

2. Description of the Related Art Conventional active hosts and standby hosts are:
As shown in the published patent publication "Online Business Switching System" (Japanese Patent Laid-Open Publication No. Hei 5-346868, hereinafter referred to as Document 1), a one-to-one configuration is generally used. Executes a main job such as an online transaction system, and the standby host performs an application job other than the main job such as a cold standby state, that is, a state where no job is performed, or an active system. Is common. In addition, in the state where the efficiency of the system is regarded as the most important, as in recent times, there are many cases where some kind of application job is fully executed as in the latter case.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned conventional working system,
In the standby system, when the load of the standby host switched in the event of a failure in the active system is high, there is a risk that the main job performed by the active system cannot be completely executed.

[0004] An object of the present invention is to prepare a plurality of standby hosts according to the recent trend of multiprocessor orientation and distributed system orientation, and in the event of a failure of the active host, the host with the lowest load is used as the switching destination host. An object of the present invention is to provide a working / standby switching method that can be determined, thereby improving the utilization efficiency of the working / standby system as a whole.

[0005]

According to a first aspect of the present invention, there is provided an active / standby switching system in an active / standby system having a plurality of standby hosts with respect to an active host. A load monitoring means for monitoring the load on the host, and upon receiving a switching instruction, confirms the necessity of switching the active host by a predetermined method, and outputs a switching unnecessary signal when switching is not necessary, and switches the host. In such a case, the system further comprises switching control means for activating a standby transaction system for taking over the active transaction system provided in the host in advance, wherein the active host is configured so that each of the standby hosts has a predetermined cycle. Comparing the loads notified from the load monitoring means, and instructing the standby host having the smallest load to perform the switching instruction. A switching determining means for performing switching host determination processing to be output and continuing the switching host determination processing when receiving the switching unnecessary signal in response to the switching instruction; and the active transaction system for processing an active transaction. It is characterized by.

According to a second aspect, in the first aspect, the load monitored by the load monitoring means is:
It is characterized in that the ratio required for the CPU to execute a job per unit time in the spare host including the load monitoring means is used as a reference.

In a third aspect based on the first aspect, the load monitored by the load monitoring means is:
The number of programs being executed on the spare host including the load monitoring means is set as a reference.

In a fourth aspect based on the first aspect, the load monitored by the load monitoring means is:
The load of the input / output device for inputting / outputting to / from a peripheral device in the spare host including the load monitoring means is set as a reference.

[0009]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the working / standby switching system of the present invention.

The active / standby switching system of the present embodiment includes a central processing unit load monitoring means 1, 2, a switching control means 8, 9, a standby transaction system 11, 12, and The active host 13 includes a switching host determination unit 7 and an active transaction system 10. It is assumed that there are two standby hosts, but the present invention is exactly the same as the case of two or more hosts.

The central processing unit load monitoring means 1 and 2 in the standby hosts 14 and 15 are host load monitoring means for monitoring the loads on the hosts 14 and 15.

The active transaction system 10 includes:
This is a transaction system that performs online operations, and is a backup transaction system 11, 12.
Is a transaction system that takes over the business when a failure occurs in the active transaction 10 or the host 13 where the active transaction system exists.

The hosts 13, 14, and 15 are computer systems on which a transaction system operates.

FIG. 2 is a flow chart showing the processing of the entire system in the active / standby switching method of the present invention.

This processing is performed by a switching host determination processing 21
And a switching check process 22 and a switching process 23.

Next, a description will be given, with reference to FIG.

In the switching host determination process 21, when a failure occurs in the active transaction system 10 or the host 13 in which the active transaction system exists, a host having a standby transaction system to be switched is determined.

The switching host is determined by the hosts 14, 1
5 is performed by the switching host determination unit 7 based on the load of the central processing unit monitored by the central processing unit load monitoring units 1 and 2. The switching host determination unit 7 compares the loads of the central processing units of the host 14 and the host 15 obtained by the central processing unit load monitoring units 1 and 2 at a predetermined period, and determines whether the load of the central processing unit is lower. Is determined to be the switching host. Thereafter, the switching control means 8 or 9 of the host determined to be the switching host includes:
Notify that it is the switching host. That is, a host with a low load on the central processing unit determines that there is enough time to execute the transaction system, and determines that it is a switching host. In addition, the switching host determination unit 7 notifies the switching control unit 8 or 9 that has not been determined as the switching host that it is not the switching host.

The switching control means 8 or 9 of the host determined to be the switching host performs the switching check processing 2
Second, it is checked whether it is necessary to switch the work of the active transaction system to the backup transaction system due to a failure of the active transaction system 10 or the host 13 where the active transaction system exists.

If it is determined in the switching check processing 22 that "there is no need to switch", that is, if it is determined that the active system is operating normally, the switching control means 8 or 9 switches to the active system. An unnecessary signal is output, and in response to the signal, the switching host determination unit 7 of the active system repeatedly performs the switching host determination processing 21. By repeatedly performing the switching host determination process, the switching destination host is always determined by the latest load of the central processing unit.

On the other hand, if it is determined in the switching check 22 that “switching is necessary”, a switching process 23 is performed. It should be noted that whether or not the active system is operating normally in the switching control means 8 or 9 is determined according to the conventional technique.
For example, this is performed using a watchdog timer or the like.

The switching process 23 is a switching host determination process 21 in which the switching host determining means 7 is performed by the switching control means 8 or 9 which has notified the switching host. On the other hand, the switching control unit that has been notified that the host is not the switching host does not perform any processing.

The switching control means 8 or 9 notified of the switching host instructs the backup transaction 11 or 12 in the same host to take over the work of the active transaction system. A method of switching the active transaction system to the standby transaction system is described in, for example, the document 1 described in the section of “Prior Art”.

Thus, the processing of the working / standby switching system of this embodiment is completed.

In this embodiment, load monitoring is realized by the central processing unit monitoring means 1 and 2 as described above.
The determination of the switching host in the switching host determination processing 21 is performed based on monitoring by the central processing unit load monitoring means 1 and 2. Some specific examples of the load monitoring method will be described below.

(1) Program monitoring method: This is a method based on the number of programs being executed by the host computer as a load. FIG. 3 is a block diagram showing a case where the program monitoring means 3 and 4 for monitoring the program are used as the central processing unit load monitoring means 1 and 2 in FIG.

Referring to FIG. 3, the switching host determining means 7 determines the switching host in the switching host determination processing 21 based on the program monitoring means 3 and 4. At this time, the number of programs being executed by the host 14 and the host 15 is compared, and the one with the smaller number of programs being executed is determined to be the switching host. That is, it is determined that the smaller number of programs being executed has room for execution of the transaction system, and it is determined that the host is the switching host.

(2) I / O device load monitoring method: A method based on the load of an I / O device that performs input / output between a host and a peripheral device such as a magnetic disk as a load. FIG.
FIG. 2 is a configuration diagram in the case where input / output device load monitoring units 5 and 6 that monitor the load of the input / output device are used as the central processing unit monitoring units 1 and 2 in FIG. 1.

Referring to FIG. 4, in the switching host determination process 21, the switching host determination unit 7 determines the switching host based on the input / output device load monitoring units 5 and 6. At this time, the load of the input / output device for inputting / outputting the peripheral device between the host 14 and the host 15 is compared, and the one with the lower load is determined as the switching host. That is, it is determined that the one with the lower load on the input / output device has room for execution of the transaction system, and is determined as the switching host.

(3) A method for monitoring the job execution time of the CPU;
This method is based on the ratio of the CPU required to execute a job to the unit time in the self-reserve host.

Although not shown, the switching host determining means 7 determines the host 1 in the switching host determination processing 21.
4 and the host 15 compare the ratio required for the CPU to execute the job with respect to the unit time, and determine that the smaller ratio is the switching host.

[0033]

As described above, according to the present invention, a plurality of spare hosts are prepared, and when selecting the spare host to which the active transaction system is to be switched, the one with the lowest load is selected, and the current operation is performed. By being able to take over, the job execution load of the spare host at the time of switching is high, so that there is an effect that the risk that the current transaction cannot be executed is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing the flow of processing in the embodiment.

FIG. 3 is a block diagram when a program monitoring unit is used as a central processing unit load monitoring unit in FIG. 1;

FIG. 4 is a block diagram when an input / output device load monitoring unit is used as a central processing unit load monitoring unit in FIG. 1;

[Explanation of symbols]

 1, central processing unit load monitoring means 3, 4 program monitoring means 5, 6 input / output load monitoring means 7 switching host determination means 8, 9 switching control means 10 active transaction system 11, 12, standby transaction system 13, 14, 15 Host

Claims (4)

(57) [Claims] In a working / standby switching system in a working / standby system having a plurality of standby hosts with respect to an active host, each of the standby hosts includes load monitoring means for monitoring a load of the host. When a switching instruction is received, the necessity of switching of the active host is confirmed by a predetermined method. If switching is not required, a switching unnecessary signal is output, and if switching is required, the host is prepared in the host in advance. Switching control means for activating a standby transaction system for taking over the active transaction system, wherein the active host comprises:
At a predetermined cycle, the load notified from the load monitoring means of each of the standby hosts is compared, and a switching host determination process of outputting the switching instruction to the standby host having the smallest load is performed. An active / standby switching system, comprising: a switching determining means for continuing the switching host determining process when the switching unnecessary signal is received as a response; and the active transaction system for processing an active transaction. 2. The load monitored by the load monitoring unit is based on a ratio of a CPU required to execute a job to a unit time in the spare host including the load monitoring unit. Working / standby switching method described. 3. The active / standby switching according to claim 1, wherein the load monitored by the load monitoring unit is based on the number of programs being executed in the spare host including the load monitoring unit. method. 4. The load monitored by the load monitoring unit is based on a load of an input / output device that performs input / output with a peripheral device in the spare host including the load monitoring unit. Item 1. A working / standby switching method according to item 1.