JPH07311718A - Duplex system - Google Patents

Abstract

PURPOSE:To obtain a duplex system wherein an in-operation system device can secure a SCSI bus even when both two devices try to secure the SCSI bus by providing a monitor means which makes a request to set a SCSI ID again and requests the in-operation system device to perform switching to the stand-by system. CONSTITUTION:A monitor task 3, which have detected abnormality, requests a device 1 to stop and a SCSI control part 21 to set a SCSI ID again. The device 1 receiving the request to stop stops its function. The SCSI control part 21 having received the request to set the SCSI ID again sets (validates) the SCSI ID again and the device is reactuated as the in-operation system. Thus, if the in-operation system device 1 becomes abnormal, the ID of the stand-by system device 2 is changed into an ID whose access instruction is effective and the ID of the in-operation system device 1 is changed into an ID whose access instruction is not effective. Therefore, even when the in-operation system device 1 is accessed by mistake, its ID is not effective, so the stand-by device 2 can secure the SCSI bus and its operation can be guaranteed.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the same SCSI (Sma)
ll Computer System Interf
access) bus, and is related to a duplex system including a device having a SCSI control unit capable of resetting a SCSI ID.

[0002]

2. Description of the Related Art An example of this type of duplex system is known from Japanese Patent Laid-Open No. 4-31138.

In this duplication system, when an abnormal condition that obstructs access to the input / output device occurs, the main controller stops functioning when the abnormal condition occurs and the main controller ID The sub controller outputs the change command, and in response to the reception of the ID change command, the sub controller changes the ID code at the time of initialization to ID data for which the access command from the host computer is valid, and the input / output device according to the access command. To control data transfer with the host computer.

[0004]

In the above-mentioned conventional system, when an abnormality occurs, the ID of the sub controller (standby system device) is changed to an ID for which the access command is valid. System device ID
Has not been changed, and the ID of the main controller is an ID for which the access command is valid. Therefore, if the SCSI bus is secured from both controllers at the same time, the SCSI IDs of both controllers are the same, so However, there is a problem that the SCSI bus cannot always be secured.

The purpose of the present invention is to have both devices simultaneously use SCSI.
It is an object of the present invention to provide a duplication device in which the operating system device can always secure the SCSI bus even if the bus is secured.

[0006]

The duplication system of the present invention monitors both devices and detects an abnormality of the operation system device.
Requests the operating system to stop, requests the SCSI control unit of the standby system to reset the SCSI ID so that the access command is valid, requests the standby system to switch to the active system, and waits. When receiving that the active device has switched to the active system, it requests the SCSI ID to be reset so that the access command to the SCSI control unit of the previous active device becomes invalid, and the previous active device switches to the standby system. Has a monitoring means for requesting.

[0007]

According to the present invention, when an abnormality occurs in the active system device, the ID of the standby system device becomes the ID for which the access command is valid.
And the ID of the operation system device is changed to an ID for which the access command is not valid. Therefore, even if the active device is mistakenly accessed, the ID is not valid.
The CIS bus can be secured and its operation is guaranteed.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram of a duplex system according to an embodiment of the present invention, FIG. 2 is a flow chart showing the operation of an active system device, FIG. 3 is a flow chart showing the operation of a standby system device, and FIG. 3 is a monitoring task. It is a flowchart which shows operation | movement of 3.

As shown in FIG. 1, the duplex system of this embodiment comprises a device 1, a device 2, and a monitoring task 3 for monitoring the devices 1 and 2, and the devices 1 and 2 are monitoring tasks 3 respectively. And SCSI control units 11 and 2 connected to the SCSI bus 4.
1 is provided.

Next, the operation of each part will be described with reference to FIGS.

First, the operation of the operation system device will be described with reference to FIG. When the monitoring task 3 requests the stop (step 101), the function is stopped (step 102). next,
The monitoring task 3 requests the SCSI controller to reset the SCSI ID (step 103), and resets the SCSI ID for which the access command is no longer valid (step 104). Next, the monitoring task 3 requests restarting (step 105), resets and restarts (step 106).

Next, the operation of the standby system device will be described with reference to FIG. When the monitor task 3 requests the SCSI controller to reset the SCSI ID for which the access command is valid (step 201), the SCSI ID is reset (step 202). Next, switching from the monitoring task 3 to the active system is requested (step 203), and the system is restarted as the active system (step 204). Then, it notifies the monitoring task 3 that it has been restarted as an active system (step 2
05).

Next, the operation of the monitoring task 3 will be described with reference to FIG. When an abnormality in the operation system device is detected (step 30
1) Request a stop to the operation system device (step 30)
2). Next, the SCSI controller of the standby system is requested to reset the SCSI ID for which the access command is valid (step 303). Next, the standby system device is requested to switch to the active system (step 304). Next, the fact that the standby system has switched to the active system is received (step 305). Next, the SCSI control unit of the previous operation system device is requested to reset the SCSI ID for which the access command is no longer valid (step 306). Finally, the previous operating system device is requested to switch to the standby system (step 30).
7).

Next, a concrete example will be described.

For example, the operation system device is the device 1, its SCSI
ID is 7, standby device is device 2, its SCSI ID
When 6 is set to 6, when an abnormality occurs in the operation system device 1, the monitoring task 3 detects the abnormality of the device 1. The monitoring task 3 that has detected the abnormality requests the device 1 to stop
The controller 21 is requested to reset the SCSI ID. The device 1 that has received the stop request stops its function. Further, the SCSI control unit 21 which has received the request for resetting the SCSI ID resets the SCSI ID to 7 (valid), and the device 2 is restarted as an active system. The device 2 that has been restarted as the active system notifies the monitoring task 3 that the restart has ended. In the monitoring task 3 notified of the restart of the device 2, the SCSI control unit 11
It requests the resetting of the ID, and further requests the device 1 to restart. S that received the request to re-set the SCSI ID
The CSI control unit 11 resets the SCSI ID to 6 (invalid). Also, the device 1 performs a reset,
Restart as a standby system. Therefore, the device 2 restarted as the active system can always secure the SCSI bus 4 and its operation is guaranteed.

[0017]

As described above, according to the present invention, when the operating system device and the standby system device are monitored and an abnormality of the operating system device is detected, the SCSI ID of the operating system device becomes an invalid access command ID. If the SCSI bus is secured from both devices at the same time by changing to, the working system device can always secure the SCSI bus, and the operation of the working system device is guaranteed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a duplex system of an embodiment of the present apparatus.

FIG. 2 is a flowchart showing an outline of operation of an operation system device.

FIG. 3 is a flowchart showing an outline of operation of a standby system device.

FIG. 4 is a flowchart showing an operation outline of a monitoring task 3.

[Explanation of symbols]

 1 device 2 device 3 monitoring task 4 SCSI bus

Claims (2)

[Claims] 1. SCSI connected to the same SCSI bus
In a duplex system composed of devices having a SCSI control unit capable of resetting an ID, both devices are monitored, and if an error is detected in the active system device, a stop request is issued to the active system device and the standby system SCSI device When the controller is requested to reset the SCSI ID so that the access command becomes valid, the standby system device is requested to switch to the active system, and the standby system device receives the change to the active system, It is characterized in that it has a monitoring means for requesting resetting of the SCSI ID so that the access command to the SCSI control unit of the previous operating system device becomes invalid, and requesting the previous operating device to switch to the standby system. Duplication system. 2. The duplex system according to claim 1, wherein when the previous operation system device is requested to switch to the standby system, it is reset and restarted as a standby system.