JP2606144B2 - Redundant device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as an apparatus for duplicating storage in order to increase the reliability of a computer device. The present invention relates to an improvement in an apparatus that includes an active system and a standby system, and that matches the storage content of a standby system with the storage content of an active system. The present invention relates to an improvement in reducing power consumption and detecting a failure in an active system from a standby system.

[0002]

2. Description of the Related Art Conventionally, a device capable of performing storage and control equivalent to that of an active system is provided as a standby system, and the storage contents of the standby system are made to match the storage contents of the active system. When a failure occurs in the system, switch the device that was on standby as the standby system to the active system,
Technologies for improving the reliability of computer devices are known.

[0003] In such a duplex apparatus, an apparatus which is in a standby state as a standby system is operated in the same manner as an apparatus which is operated as an active system. Further, in such a redundant apparatus, a failure that has occurred in the active system is performed by detecting a plurality of pieces of information by a plurality of methods. It is designed to detect.

[0004]

If the apparatus in the standby state as the standby system is operated in the same manner as the apparatus operating as the active system, the same power is consumed. In addition, it is convenient to detect a failure that has occurred in the active system inside the active system. However, if a failure occurs in the control unit of the active system, the function of detecting the failure is lost. In some cases, notification of a failure occurrence and switching between the active system and the standby system may become impossible.

As a duplexer for controlling a clock signal related to the present invention, a technique described in Japanese Patent Application Laid-Open No. Hei 4-247531 is known. This is a technique for making the phases of the clock signal of the apparatus serving as the standby system coincide with each other to accurately match the operations. Japanese Patent Laid-Open Publication No. Hei 4 (1994) discloses a duplex system for detecting a failure by comparing a signal output from a device on the other end with a signal output from the own device.
The technique described in JP-A-350730 is known.

SUMMARY OF THE INVENTION The present invention has been made in such a background, and reduces the power consumption of a device set as a standby system. It is an object of the present invention to provide a duplexer capable of detecting a failure of a device which has been installed, improving reliability, and providing a small-scale additional device for detecting a failure of another system.

[0007]

SUMMARY OF THE INVENTION The present invention reduces the power consumption of an apparatus for duplicating storage and keeping the storage contents of a standby system coincident with the storage contents of an active system, and furthermore, the failure of the active system from the standby system side. Is provided with two duplicated devices each including a storage unit and a control unit, and one of the two devices is set as an active system and the other is set as a standby system and set as an active system. An upper-level device that switches between the active system and the standby system when a failure is detected in the device, and a communication line that interconnects a storage unit between the two devices, and the control unit includes the communication line In a duplexer comprising control means for performing communication one or more times within a predetermined time so as to match the storage content of the standby storage unit with the storage content of the active storage unit via the control unit, the control unit includes: During periods other than the communication period Characterized by comprising a means for stopping the clock signal to be supplied to the storage portion of the device that is set as a system.

[0008] Each of the two devices is provided with another system monitoring unit, and the other system monitoring unit sends a specific control signal of the device set as the active system when the own device is set as the standby system. Means for monitoring, wherein the means for monitoring the control signal identifies the device set to the active system as a failure state when the control signal of the device set to the active system does not continuously change for a certain period of time. Means, the specific control signal is a control signal transmitted to copy the storage content of the active storage unit to the standby storage unit, and the control unit is configured to receive the active control signal from the other system monitoring unit. Means for notifying the higher-level device when an identification output indicating that the device set in the system is in a failure state is transmitted, and the higher-level device is provided with If the device set for the system is It is desirable to provide means for switching between active and standby systems when it is notified that was harmful.

[0009]

The communication for matching the contents of the storage unit from the active system to the standby system is not always performed continuously during the operation of the apparatus. This communication is performed intermittently when there is a change in the contents of the active storage unit, and it is necessary to supply a clock signal to the standby storage unit during periods when communication is not being performed. There is no. Therefore, in the device set as the standby system, the clock signal supplied to the storage unit that holds the storage content that matches the storage unit of the active system is stopped during a period in which communication between the active system and the standby system is not performed. By doing so, when it is not necessary to rewrite the contents of the storage unit, the operation of the storage unit is substantially stopped, and the power consumption of the standby system can be reduced.

Further, a change in the control signal transmitted from the standby system to the working system is detected, and if this does not change for a certain period of time, it is assumed that a failure has occurred in the working system, thereby controlling the working system. If the circuit fails,
Even when the self-failure cannot be transmitted to the higher-level device, the standby system can be switched. That is, the overall reliability can be improved.

As the control signal transmitted from the standby system to the active system, it is preferable to use a control signal for rewriting the contents of the storage unit of the standby system. With this configuration, it is possible to detect a failure of the partner device without particularly adding a connection circuit.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

In the embodiment of the present invention, the storage units 02, 1
2 and two control units 01 and 11
A system device and a system 1 device are provided. One of the two system 0 devices and the system 1 device is set as the active system and the other is set as the standby system. When a failure is detected in the device set as the active system, the active system is set. A higher-level device 300 that switches between the standby system and the standby system;
A communication line interconnecting the storage units 02 and 12 between the two systems 0 and 1;
1 stores the storage contents of the storage unit 12 or 02 serving as the standby system via this communication line in the storage unit 02 or 1 serving as the active system.
Control means for performing communication one or more times within a predetermined time so as to match the stored contents of 2. The feature of the present invention is that the control units 01 and 11 include a standby system during periods other than the period for performing the communication. Means for stopping a clock signal to be supplied to the storage unit 12 or 02 of the device set as "1".

Further, the two 0-system devices and the 1-system device are provided with other-system monitoring units 04 and 14, respectively. These other-system monitoring units 04 and 14 are used when the own device is set to the standby system. Means for monitoring a specific control signal of a device set in the system, wherein the control signal is monitored when the control signal of the device set in the active system does not change continuously for a certain period of time. Means for identifying a device set in the system as a failure state is included.

The specific control signal is stored in the active storage unit 0.
The storage contents of 2 or 12 are stored in the storage unit 12 or 0 of the standby system.
The control unit 01, 11 sends an identification output indicating that the apparatus set as the active system is in a failure state from the other system monitoring units 04, 14. At this time, there is provided a means for notifying this to the upper-level device 300, and the upper-level device 300 becomes active when notified from the device set as the standby system that the device set as the active system has failed. A means for switching between the system and the standby system is provided.

The 0-system device and 1-system device of each of the lower devices 100 and 200 are connected by the data communication signal line b and the inter-system communication control signal lines 0a and 1a, and the upper device 300 is connected to the lower devices 100 and 200. Connected. The control units 01 and 11 control the entire system of the 0-system device and the 1-system device provided in the lower-level devices 100 and 200,
The storage units 02 and 12 hold data necessary for the operation of the apparatus, and perform data communication processing with the 0-system apparatus and the 1-system apparatus.

The clock control units 03 and 13 are set to 0
The other system monitoring units 04 and 14 monitor the communication state of the inter-system communication control signal lines 0a and 1a during the operation of the standby system device, and control the clock control units 03 and 13 by controlling the supply of the system and system 1 clocks. When an abnormality occurs in inter-system communication, an alarm is notified to the control units 01 and 11. The first system device serving as the standby system usually includes the storage unit 12 and the control unit 1.
The operation is stopped so as to reduce the power consumption by stopping the transmission of the clock signal to be supplied to 1.

Here, the operation of the embodiment of the present invention configured as described above will be described. FIG. 2 is a diagram showing operation timing in the embodiment of the present invention.

First, when the 0-system device of the lower-level device 100 is the active system and the 1-system device is the standby system, the storage unit 0 of the active system
The operation when the data 2 is normally transmitted to the standby system at regular intervals to update the data in the standby system will be described.

The working storage unit 02 transmits data via the data communication signal line b after enabling the inter-system communication control signal line 0a. The other-system monitoring unit 14 of the standby system controls the clock control unit 13 based on the monitoring result of the inter-system communication control signal line 0a. When detecting that the inter-system communication control signal line 0a has changed and is now operable, the other-system monitoring unit 14 of the standby system causes the clock control unit 13 to start supplying a clock signal via the clock control signal line 1c. The standby storage unit 12 receives the clock signal from the clock control unit 13 and starts receiving data sent from the active storage unit 02. The storage unit 02 of the active system makes the inter-system communication control signal line 0a inoperable when the data transmission is completed. Upon detecting the change, the standby-system other-system monitoring unit 14 stops supplying the clock signal to the clock control unit 13 via the clock control signal line 1c, and ends the data reception.

Next, a description will be given of the operation in the case where a failure has occurred in the active system 0 side and data cannot be normally transmitted to the standby system.

The other-system monitoring unit 14 for the standby system monitors the time since the inter-system communication control signal line 0a becomes inoperable, and monitors the inter-system communication control signal line 0 for a predetermined time or more.
When it is detected that a has not changed, the clock control unit 14 starts supplying the clock signal via the clock control signal line 1c, and the control unit 11 sends the alarm signal line 1d
Notify alarm from. The control unit 11 of the standby system notifies the host device 300 of the occurrence of an abnormality in inter-system communication.

According to such an operation, the standby system device can autonomously detect a failure in inter-system communication for updating the standby system data and notify an alarm.

[0024]

As described above, according to the present invention, the power supply of the standby system is reduced by stopping the supply of the internal clock signal at a time other than the inter-system communication for updating the data of the standby system. In some cases, a failure in inter-system communication can be autonomously detected on the standby side, so that abnormal data is not received from the active side, and the reliability of the apparatus can be improved.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing operation timing in the embodiment of the present invention.

[Explanation of symbols]

 01, 11 Control unit 02, 12 Storage unit 03, 13 Clock control unit 04, 14 Other system monitoring unit 100, 200 Lower device 300 Upper device 0a, 1a Inter-system communication control signal line b Data communication signal line 0c, 1c Clock control Signal line 0d, 1d Alarm signal line

Claims (5)

(57) [Claims] An apparatus is provided with two redundant devices each including a storage unit and a control unit. One of the two devices is set as an active system and the other is set as a standby system. A higher-level device that switches between the active system and the standby system when detected, and a communication line that interconnects the storage units between the two devices; the control unit includes a standby line via the communication line; In a duplexer equipped with control means for performing communication one or more times within a predetermined time so as to match the storage content of the system storage unit with the storage content of the active system storage unit, the two devices each have a different system monitoring unit. In addition to this
The system monitoring unit displays the current status when the own device is set to the standby system.
Monitors a specific control signal of the device set in the system
Means, and the means for monitoring the control signal is provided in the working system.
The control signal of the specified device changes continuously for a certain period of time.
Device that is set as the active system when the
A duplication device comprising means for identifying as a device. 2. The system according to claim 1, wherein the specific control signal is a storage unit of an active system.
Sent to copy the storage contents of
2. The duplexing device according to claim 1 , wherein the control signal is a control signal . 3. The contents stored in the storage unit of the active system are stored in the storage unit of the standby system.
Monitoring of the control signal sent out for copying to the memory
Depending on the result, the clock signal to be supplied to the standby storage unit
3. The duplexing device according to claim 2, further comprising means for stopping the operation . 4. The control unit includes means for notifying the higher-level device when an identification output indicating that the device set as the active system is in a failure state is transmitted from the other-system monitoring unit. 3. The duplexer according to claim 2, further comprising: 5. The system according to claim 4, wherein the higher-level device switches between the active system and the standby system when being notified from the device set as the standby system that the device configured as the active system has failed. The duplication device according to the above.