select inst_id, instance_number, instance_name, host_name, version, startup_time, status, parallel, thread#, archiver, log_switch_wait, logins, shutdown_pending, database_status, instance_role, active_state, blocked from gv$instance;
instance_role
can be used to determine if an instance is an active instance (=primary instance) or a secondary instance (in a standby environment) dbms_utility.get_time
.