let us find out the database health status by using following sql command. - Check whether the Oracle Process run or not#> ps -ef | grep pmon If no pmon detected, your database might be down - Check the instance status SQL>select instance_name, status from v$instance; - Check whether the database can be read or write SQL>select name, open_mode from v$database; Check whether client can access the database - Check whether the listener is available or not #> lsnrctl status - Do tnsping from remote site #> tnsping SID