Modes, Roles, and States
The mode of an EMS server is determined by its configuration, and dictates how it operates in its environment. If a fault tolerant mode is selected, two EMS servers are required and each operates in a defined role. How an EMS server is operating at any given moment can be determined by viewing its fault tolerant state.
For example, an EMS server operating in fault tolerant mode can play either a primary or secondary role. Once both EMS servers in the fault tolerant pair have been started, one of the two servers will be in the active state while its peer will be in the standby state. In the event of a failover, the server that was standby becomes active.
Modes
By default, the EMS server operates in standalone mode. However, it can also be configured to run in a fault tolerant mode:
- Standalone — the default EMS server mode.
- Classic Fault Tolerant — configured through the ft_active parameter.
Roles
Each server operating in a fault tolerant mode has a distinct role: primary or secondary.
These roles are implicit for EMS servers started using tibemsd.conf files. They are explicit for EMS servers started using a JSON configuration file. For JSON-configured servers, the primary server is the EMS server started without the -secondary command line parameter, while the secondary server is started with it. In the .conf files, each server in the fault tolerant pair has a distinct tibemsd.conf file.
States
The state of the EMS server tells you about its current operations.
Use the info or show state command in the administration tool to determine the state of the EMS server.