Enabling ARCHIVELOG Mode

Enabling Archive log

Lets start by checking the current archive mode.

SELECT LOG_MODE FROM SYS.V$DATABASE;

LOG_MODE

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

NOARCHIVELOG

In INIT.ora file add the following parameter

############################

# Archive Log Destinations -benr(10/15/04)

############################

log_archive_dest_1='location=/u02/oradata/MONT/archive'

log_archive_start=TRUE

Note that we're not actually required to specify the location of the log destination, but if you don't it'll end up in strange places (in my test it went to $ORACLE_HOME/dbs making a mess). You can specify as many as 10 diffrent archive log destinations by using the paramters log_archive_dest_1 through log_archive_dest_10. Remember, if you run out of space in your archive log destination the database will shut down!

Now we can startup the database in mount mode and put it in archivelog mode.

startup mount

alter database archivelog;

alter database open;

There are several system views that can provide us with information regarding archives, such as:

V$DATABASE

Identifies whether the database is in ARCHIVELOG or NOARCHIVELOG mode and whether MANUAL (archiving mode) has been specified.

V$ARCHIVED_LOG

Displays historical archived log information from the control file. If you use a recovery catalog, the RC_ARCHIVED_LOG view contains similar information.

V$ARCHIVE_DEST

Describes the current instance, all archive destinations, and the current value, mode, and status of these destinations.

V$ARCHIVE_PROCESSES

Displays information about the state of the various archive processes for an instance.

V$BACKUP_REDOLOG

Contains information about any backups of archived logs. If you use a recovery catalog, the RC_BACKUP_REDOLOG contains similar information.

V$LOG

Displays all redo log groups for the database and indicates which need to be archived.

V$LOG_HISTORY

Contains log history information such as which logs have been archived and the SCN range for each archived log.

Using these tables we can verify that we are infact in ARCHIVELOG mode:

SQL> select log_mode from v$database;

LOG_MODE

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

ARCHIVELOG

SQL> select DEST_NAME,STATUS,DESTINATION from V$ARCHIVE_DEST;