The SMA server node can be made highly available with the solidDB® HotStandby component.
In an SMA with HotStandby setup, there can be one or more SMA applications on each node. The application connection to the database can be configured as a regular SMA connection (SMA Basic Connectivity) or as a Transparent Connectivity SMA connection (SMA TC). With both connectivity types, the application on the Primary node uses an SMA connection to execute reads and writes locally, and the application on the Secondary uses an SMA connection to execute reads locally. Additionally, with SMA TC connection, write transactions from the application on the Secondary can be executed on the Primary server using a network connection. Furthermore, if the load balancing option is enabled with the SMA TC connection, the applications can operate in an active-active manner; on each node, the full functionality of database access is available.
With SMA TC, the application on each node must be able to connect to the local server with a SMA connection and to the remote server with a network-based connection.
Failover and switchover handling
▪The connection handle is maintained over switchovers and failovers for as long as one of the servers is in the PRIMARY ACTIVE, PRIMARY ALONE, or STANDALONE state.
▪If the SMA server fails, the application might fail also. To ensure high availability in such a failure scenario, your system needs to include an application-level failover mechanism that moves the service offered by the application from the failed application instance to another one.
