Oracle DB Archive log mode enable step

 

Check the database version which database version you work

SQL> select banner from v$version;

 

BANNER

--------------------------------------------------------------------------------

Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production

PL/SQL Release 12.2.0.1.0 - Production

CORE     12.2.0.1.0             Production

TNS for Linux: Version 12.2.0.1.0 - Production

NLSRTL Version 12.2.0.1.0 - Production

Step-2: we can check the given below  command that I have checking archive log mode is open or not. I have write given below command and got the output.

SQL> archive log list

Database log mode                No Archive Mode

Automatic archival                  Disabled

Archive destination                /u01/app/oracle/product/12.2.0.1/db_1/dbs/arch

Oldest online log sequence     46

Current log sequence           48

Step-3: check the archive log destination with write the given below command:

SQL> show parameter DB_RECOVERY_FILE_DEST

 

NAME                                                        TYPE VALUE

------------------------------------ ----------- ------------------------------

db_recovery_file_dest                       string

db_recovery_file_dest_size             big integer 0

Step-4:  We are enable oracle database archive mode  and given below following step need to archive log mode enable and open it. It is also recommended before archive log mode is open , it’s better practice take database image backup .  

SQL> shut immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

Step-5: startup database in mount state mode

SQL> startup mount

ORACLE instance started.

 

Total System Global Area 1509949440 bytes

Fixed Size                                8793016 bytes

Variable Size                        570426440 bytes

Database Buffers               922746880 bytes

Redo Buffers                          7983104 bytes

Database mounted.

Step-6: apply command for enable archive log Mode

SQL> alter database archivelog;

 

Database altered.

Ste-7: Apply command Database in open mode

SQL> alter database open;

 

Database altered.

Step-8: Checking database archivelog mode enable

SQL> archive log list

Database log mode                Archive Mode

Automatic archival                  Enabled

Archive destination                /u01/app/oracle/product/12.2.0.1/db_1/dbs/arch

Oldest online log sequence     46

Next log sequence to archive   48

Current log sequence           48

Oracle db_name vs oracle_unique_name (RAC , data guard and MAA

 

Names Among MAA

Under Oracle Maximum Availability Architecture (MAA), we might be confused about various kinds of name. Here I try to clarify these names by chart and table.

DB_NAME (Enterprise-wide Name)

You must set this parameter for every instance in order to startup the database. If you didn't assign DB_NAME at installation-time, then

DB_NAME = $ORACLE_SID

DB_UNIQUE_NAME (Site-wide Name)

If you didn't assign DB_UNIQUE_NAME in the parameter file at startup-time, then

DB_UNIQUE_NAME = DB_NAME

If you didn't assign SERVICE_NAMES in the parameter file at startup-time, then

SERVICE_NAMES = DB_UNIQUE_NAME

INSTANCE_NAME (Server-wide Name)

If you didn't assign INSTANCE_NAME in the parameter file at startup-time, then

INSTANCE_NAME = $ORACLE_SID

Naming Scope and Default Values

Parameter Name	Name Scope	Default Value	Level
DB_NAME	Enterprise-wide	= $ORACLE_SID (Installation-time)	Database
DB_UNIQUE_NAME	Site-wide	= DB_NAME (Startup-time)	Role
SERVICE_NAMES	Site-wide (or Enterprise-wide)	= DB_UNIQUE_NAME (Startup-time)	Role (or Database)
INSTANCE_NAME	Server-wide	= $ORACLE_SID (Startup-time)	Instance
$ORACLE_SID	Server-wide	N/A	Instance

The above featured image illustrates you a hierarchy tree for better understanding on the relationship among names. For more details, you may check DB_NAME and DB_UNIQUE_NAME in Oracle documentation.