You can add one or more Permanent Standby servers to an existing Hot-Standby or Triple Standby architecture. Adding Permanent Standby servers is useful when you need to reduce the load on the system as they allow managers, administrators, and analysts to access the data on the system without affecting the resources of the Main and Standby servers.
The number of Permanent Standby servers you can add depends on the type of system architecture you already have in place:
- On a Hot-Standby Pair, you can add up to four Permanent Standby servers.
- On a Triple Standby system, you can add up to three Permanent Standby servers, but each Permanent Standby server can only connect to two of the three Main/Standby servers.
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A Permanent Standby server can only connect to two of the three servers in a Triple Standby architecture. You specify the connection to the two servers in the configuration for the Permanent Standby server. Usually, Permanent Standby servers are configured to connect to the two servers that are most likely to go Main (i.e. the two servers with the highest Cost settings).
When you add a Permanent Standby server to a system, you need to perform configuration tasks on the server that starts as Main and the server(s) that starts as Standby as well as the Permanent Standby server. This is because each server needs to be able to recognize the other servers that connect to it.
To add a Permanent Standby server to an existing system, you need to:
- Log on to the Permanent Standby that you are adding and configure it to recognize the Main server and the Standby server(s) (see Configure a Permanent Standby Server).
- On the Permanent Standby server, install the same drivers that are already installed on the Main server.
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ATTENTION: You should install the same drivers on the Permanent Standby server as those installed on the Main server. If the Main server has drivers that are not installed on the Permanent Standby, the Permanent Standby server will not be able to establish a connection with the Main server.
- Repeat steps 1 and 2 for each Permanent Standby server that you are adding to the system architecture.
- Log on to the server that starts as Main and configure it to recognize each Permanent Standby server (see Configure the Main Server to Recognize a Permanent Standby Server).
- Log on to the Standby server and configure it to recognize each Permanent Standby server (see Configure a Standby Server to Recognize a Permanent Standby Server). On Triple Standby systems, you need to configure each Standby to which the Permanent Standby servers connect. This may be one or both of the Standby servers depending on the set up of your system.