CREATE spfile FROM pfile;
startup;

select status,target,archiver,error,process from v$archive_dest;

select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP
------------------------------ ----- -----
SYS                            TRUE  TRUE

select max(sequence#) from v$archived_log;

select switchover_status from v$database;

NOT ALLOWED - Either this is a standby database and the primary database has
    not been switched first, or this is a primary database and there are no standby databases. 

    SESSIONS ACTIVE - Indicates that there are active SQL sessions attached to 
    the primary or standby database that need to be disconnected before the 
    switchover operation is permitted. 

    SWITCHOVER PENDING - This is a standby database and the primary database 
    switchover request has been received but not processed. 

    SWITCHOVER LATENT - The switchover was in pending mode, but did not complete
    and went back to the primary database. 

    TO PRIMARY - This is a standby database, with no active sessions, that is 
    allowed to switch over to a primary database. 

    TO STANDBY - This is a primary database, with no active sessions, that is 
    allowed to switch over to a standby database. 

    RECOVERY NEEDED - This is a standby database that has not received the 
    switchover request. 

    During normal operations it is acceptable to see the following values for 
    SWITCHOVER_STATUS on the primary to be SESSIONS ACTIVE or TO STANDBY.  
    During normal operations on the standby it is acceptable to see the values 
    of NOT ALLOWED or SESSIONS ACTIVE.

show parameter log_archive_config

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_config                   string      DG_CONFIG=(thadgdb5,thadgdb6)