Normally, you need to start a RepAgent thread only if:
You have reconfigured the RepAgent parameters.
You have explicitly shut down the RepAgent.
RepAgent starts automatically when Adaptive Server restarts if the RepAgent has been started at least once with sp_start_rep_agent and not stopped with sp_stop_rep_agent.
To start RepAgent, log in to Adaptive Server and enter sp_start_rep_agent at the isql prompt. For example:
sp_start_rep_agent pubs2
In this example, pubs2 is the name of the database for which the RepAgent has been enabled.
RepAgent can be restarted only if its associated database is fully recovered and online and log transfer is on for the connection to the primary database.
Refer to Chapter 5, “Adaptive Server Commands and System Procedures,” in the Replication Server Reference Manual for detailed information about each option of sp_start_rep_agent.