5.11 Performing Automatic Degradation Using the Arbitration Server

If database multiplexing is performed using WebAdmin, it is also possible to perform automatic degradation using the arbitration server. In such cases, it is necessary to perform tasks on the database server and the arbitration server after setting up Mirroring Controller in WebAdmin.

Tasks on the arbitration server

Perform setup of the arbitration server using Mirroring Controller commands.

Set up the arbitration server.
Refer to "2.3 Setting Up the Arbitration Server" in "Chapter 2 Setting Up Database Multiplexing Mode" for information on how to set up the arbitration server.

Tasks on the database server

Change some of the settings after setting up Mirroring Controller in WebAdmin.

Set up Mirroring Controller in WebAdmin.
Refer to "5.1 Mirroring Controller Setup" for details.
Use WebAdmin to stop Mirroring Controller on the master and standby instances.
Refer to "5.4 Stopping Mirroring Controller" for details.
Edit the network configuration file of the master and standby instances, and add the arbitration server information.
The network configuration file is network.conf, which exists in the Mirroring Controller management directory specified during Mirroring Controller setup. Refer to "A.3 Network Configuration File" for details.
A definition example of network.conf is shown below.
```
Example:
The port number of the database server to be used as the arbitration network is set to "27541". The ID of the server of the Mirroring Controller arbitration process is set to "arbiter", and its port number is set to "27541".
```
```
dbsvm27500 192.0.2.100,192.0.3.100 27540,27541 server
dbsvs27500 192.0.2.110,192.0.3.110 27540,27541 server
arbiter 192.0.3.120 27541 arbiter
```
Note
- Ensure that the port numbers set for the database server and the arbitration server do not conflict with other software. In addition, do not configure the same segment for the admin network and the arbitration network.
- If the server type is "server", two IP addresses or host names, and two port numbers need to be specified in the following order:
  - IP address or host name of the database server used as the admin network
  - IP address or host name of the database server used as the arbitration network
  - Port number of the database server used as the admin network
  - Port number of the database server used as the arbitration network
- If the server type is "arbiter", specify the IP address or host name set for the my_address parameter and the port number set for the port parameter in arbitration.conf of the arbitration server.
- WebAdmin also support editing mirroring controller configuration via Use WebAdmin to edit Mirroring Controller configurations.
  Refer to "5.2 Edit Mirroring Controller Setup" for detailes.
Edit the server configuration file of the master and standby instances, and add the parameters required for automatic degradation using the arbitration server.
The server configuration file is instanceName.conf or instancePort.conf, which exists in the Mirroring Controller management directory specified during Mirroring Controller setup.
To perform automatic degradation using the arbitration server, set the heartbeat_error_action parameter to "arbitration".
Refer to "A.4.1 Server Configuration File for the Database Servers" for information on other parameters.
Use WebAdmin to start Mirroring Controller on the master and standby instances.
Refer to "5.5 Starting Mirroring Controller" for details.

Common tasks

Use the Mirroring Controller command to check the connection status from the database server or the arbitration server.
Refer to "2.8 Checking the Connection Status" for information on how to check the connection status.