Enable archive log using the below command: alter database archivelog; 5. Open the database in read, write mode. Alter database open; 6. Check the archivelog mode. SQL archive log list; Database log mode Archive Mode Automatic archival Enabled Archive destination /data/arch Oldest online log sequence 1692. Start the Database in Mount Mode. Enable Archive log. ALTER DATABASE ARCHIVELOG. Open the Database. ALTER DATABASE OPEN Now the Database is in Archivelog Mode and can be verified using the Archive Log List Command. Conn sys as sysda. Archive log list; SQL archive log list Database log mode Archive Mode. If you haven’t already done so, enabling your system to archive your Oracle 12c is a very simple process. However, keep these things in mind: You have to shut down and restart the database. You must have enough space to store your archive logs. On the other hand, oracle database must be in Archivelog mode so that we can take Full backup in online mode. If Oracle database that is in NoArchivelog mode, RMAN cannot receive Online Backup. The databases in the production environment must be in Archivelog mode and generally they are in Archivelog mode. Below are the steps to enable Archivelog mode on Oracle RAC 12c. Stop the database as grid (Both instances) srvctl stop database -d ORCL Start the database in mount mode srvctl start database -d ORCL -o mount Login to one db instances and enable archive log mode.
Since the Redologs are created at container database level in 12c and not at pluggable database level. (Enabling archivelog at pluggable database level is not possible). Archiving is done at CDB's.You can check archive log mode either by querying v$database or archivelog list
SQL> select name,open_mode,log_mode from v$database;
NAME OPEN_MODE LOG_MODE
--------- -------------------- ------------
ORCL READ WRITE NOARCHIVELOG
(OR)
SQL> archive log list
Database log mode Archive Mode
Automatic archival Disabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 11
Next log sequence to archive 13
Current log sequence 13
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To enable the Archvielog mode
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SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 788529152 bytes
Fixed Size 2929352 bytes
Variable Size 541068600 bytes
Database Buffers 239075328 bytes
Redo Buffers 5455872 bytes
Database mounted.
SQL> ALTER DATABASE ARCHIVELOG;
Database altered.
SQL> ALTER DATABASE OPEN;
Database altered.
SQL> select name,open_mode,log_mode from v$database;
NAME OPEN_MODE LOG_MODE
--------- -------------------- ------------
ORCL READ WRITE ARCHIVELOG
SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Enable Archivelog Mode
Oracle Enable Archivelog Mode
Oldest online log sequence 11Next log sequence to archive 13
Current log sequence 13