25.2.1 System configuration examples of a HiRDB/Single Server (standby system switchover)

A HiRDB/Single Server performs system switchover at the system level. System configuration examples of a HiRDB/Single Server are explained below.

Organization of this subsection
(1) Example of a 1-to-1 switchover configuration
(2) Example of a mutual system switchover configuration
(3) Sharing a utility special unit among multiple HiRDB/Single Servers
(4) Setting up a 1:1 correspondence between HiRDB/Single Servers and utility special units
(5) Setting up an m:n correspondence between HiRDB/Single Servers and utility special units

(1) Example of a 1-to-1 switchover configuration

A configuration in which there is a one-to-one correspondence between the running system and the standby system is called a 1-to-1 switchover configuration. This configuration is appropriate when it is important to guarantee response time when system switchover becomes necessary. The drawback of this configuration is that you cannot utilize the resources of the server machine in the standby system (you do not have access to the resources of one of your two server machines). Figure 25-13 shows an example of a 1-to-1 switchover configuration for a HiRDB/Single Server.

Figure 25-13 System configuration example for HiRDB/Single Servers (1-to-1 switchover configuration)

[Figure]

* This product is required in order to operate the system switchover facility in the server mode. However, it is not required when the cluster software in use is HA monitor.

Remarks
  • Each server machine requires an input/output device for use by utilities.
  • To execute a utility after system switchover has occurred, you must create on the local server machine the input/output files required to execute that utility.

(2) Example of a mutual system switchover configuration

A system configuration in which the running system has a system on the same server machine that acts as a mutual standby system (standby system for another HiRDB/Single Server) is called a mutual system switchover configuration. This configuration can be applied when multiple HiRDB/Single Servers are being used. This configuration is appropriate for making efficient use of server machine resources. However, response time slows when system switchover occurs.

Figure 25-14 shows an example of a system configuration that includes mutual system switchover for HiRDB/Single Servers. In this example, the mutual system switchover configuration is applied to HiRDB/Single Servers A and B.

Figure 25-14 System configuration example for HiRDB/Single Servers (mutual system switchover)

[Figure]

* This product is required in order to operate the system switchover facility in the server mode. However, it is not required when the cluster software in use is HA monitor.

Remarks
  • Each server machine requires an input/output device for use by utilities.
  • To execute a utility after system switchover has occurred, you must create on the local server machine the input/output files required to execute that utility.
  • In the case of a system switchover configuration, if a host name is specified in a utility control statement, you must change the host name when the systems are switched.

(3) Sharing a utility special unit among multiple HiRDB/Single Servers

Figure 25-15 shows an example of sharing a utility special unit among multiple HiRDB/Single Servers. Note that system switchover cannot be performed on utility special units.

Figure 25-15 Sharing a utility special unit among multiple HiRDB/Single Servers

[Figure]

* This product is required in order to operate the system switchover facility in the server mode. However, it is not required when the cluster software in use is HA monitor.

(4) Setting up a 1:1 correspondence between HiRDB/Single Servers and utility special units

Figure 25-16 shows an example of setting up a 1:1 correspondence between HiRDB/Single Servers and utility special units.

Figure 25-16 Setting up a 1:1 correspondence between HiRDB/Single Servers and utility special units

[Figure]

* This product is required in order to operate the system switchover facility in the server mode. However, it is not required when the cluster software in use is HA monitor.

(5) Setting up an m:n correspondence between HiRDB/Single Servers and utility special units

Figure 25-17 shows an example of setting up an m:n correspondence between HiRDB Single Servers and utility special units.

Figure 25-17 Setting up a m:n correspondence between HiRDB/Single Servers and utility special units

[Figure]

* This product is required in order to operate the system switchover facility in the server mode. However, it is not required when the cluster software in use is HA monitor.

Explanation
  • The host whose name was specified in executing the utility can select the utility special unit to be used.
  • Setting up multiple utility special units can increase the reliability of your system.