Remote standalone secondary configuration examples

The following figure illustrates an example of a configuration consisting of multiple RS secondary servers. This configuration would be useful in a situation where the primary server is located a long distance from the RS secondary servers or if the network speed between the primary server and the RS secondary server is slow or erratic. Because RS secondary servers use fully duplexed communication protocols, and do not require synchronous checkpoints processing, the primary-server's performance is usually unaffected.

Figure 1. Primary server with three RS secondary servers
This figure shows a primary server connected to three RS secondary servers.

The next illustration shows an example of a configuration of an RS secondary server along with an HDR secondary server. In this example, the HDR secondary provides high availability while the RS secondary provides additional disaster recovery if both the primary and HDR secondary servers are lost. The RS secondary server can be geographically remote from the primary and HDR secondary servers so that a regional disruption such as an earthquake or flood would not affect the RS secondary server.

Figure 2. Primary server with HDR secondary and RS secondary servers
The paragraph that precedes this figure describes the content of the figure.
If a primary database server fails, it is possible to convert the existing HDR secondary server into the primary server, as in the following diagram:
Figure 3. Failover of primary server to HDR secondary server
This figure illustrates how clients are redirected to the HDR secondary server if the primary server fails.
If the original primary is going to be offline for an extended period of time, then the RS secondary server can be converted to an HDR secondary server. Then when the original primary comes back online, it can be configured as an RS secondary server, as in the following illustration:
Figure 4. RS secondary server assuming role of HDR secondary server
This figure illustrates the RS secondary server assuming the role of an HDR secondary server.


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