HOt Clone Process

2.Enable Archive log list;
shut immediate
startup mount;
alter database archivelog;
alter database open;

3.
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /ASCPDB/app/oraascp/11.2.0/dbs/arch
Oldest online log sequence     155
Next log sequence to archive   157
Current log sequence           157

4.

select file_id,file_name from dba_data_files;
  FILE_ID FILE_NAME
---------- -------------------------------------------------
         1 /ASCPDB/oradata/TJTGHRT/system01.dbf
         2 /ASCPDB/oradata/TJTGHRT/sysaux01.dbf
         3 /ASCPDB/oradata/TJTGHRT/undotbs01.dbf
         4 /ASCPDB/oradata/TJTGHRT/users01.dbf
         5 /ASCPDB/oradata/TJTGHRT/tjtghrp_data01.dbf

5.
select group#, sequence#, status from v$log;


    GROUP#  SEQUENCE# STATUS
---------- ---------- ----------------
         1        157 CURRENT
         2        155 INACTIVE
         3        156 INACTIVE
In my case, CURRENT log sequence number : 157, GROUP# : 1


6.
To start with hot backup, all the online datafile status should be in NOT ACTIVE mode in V$BACKUP dictionary view, that displays the backup status of all online datafiles.
 select * from v$backup;

     FILE# STATUS                CHANGE# TIME
---------- ------------------ ---------- ---------
         1 NOT ACTIVE                  0
         2 NOT ACTIVE                  0
         3 NOT ACTIVE                  0
         4 NOT ACTIVE                  0
         5 NOT ACTIVE                  0

7.
SQL> alter database begin backup;

Verify status of all online datafiles after begin backup mode:
SQL> select * from v$backup;

     FILE# STATUS                CHANGE# TIME
---------- ------------------ ---------- ---------
         1 ACTIVE                2819992 30-JUL-18
         2 ACTIVE                2819992 30-JUL-18
         3 ACTIVE                2819992 30-JUL-18
         4 ACTIVE                2819992 30-JUL-18
         5 ACTIVE                2819992 30-JUL-18