How solidDB® HSB supports the N+1 (N+M) and 2N+1 (2N+M) approaches
You must make a spare server look like the server that it is replacing. Typically, this means:
▪You must copy data to the spare.
▪You must tell the spare to “listen” at the same network address as the server that it is replacing, or at another address that the client programs know to communicate through.
▪In addition, in the 2N+1 (2N+M) scenario, you must also tell the new Secondary server and the current Primary server how to communicate with each other, In other words, you must tell each of them the address to use to connect to the other.
solidDB® has two features to support such needs:
▪You can copy data to the spare server without shutting down the spare server.
▪You can set certain configuration parameters dynamically.
1 Although solidDB® configuration parameters are normally set by shutting down the server, updating the solid.ini configuration file, and then restarting the server, it is also possible to change some configuration parameters (such as the “com.listen” and “hotstandby.connect” parameters) by executing ADMIN commands similar to the following examples:
This means that a spare can be configured dynamically to take the place of another server without shutting down first. Similarly, a Primary can be told the Connect string of its new Secondary.
Tip: Executing the commands do not write the updated parameter values to the solid.ini file. To ensure that the server has the new values the next time it restarts, update the parameter values also in the solid.ini file.
Important:
The spare server must be started with the command-line option -x backupserver so that it is ready to receive the netcopy from the Primary server. For more information about the -x backupserver option, see Creating a new database for the secondary server.
2 The netcopy command copies a database to a server that is already up and running.