ARCHIVED Redolog File Management

ARCHIVED redolog files:

-->It is the dba's whether to run the database in ARCHIVELOG mode or in NOARCHIVELOG mode

-->If the database is runing in archivelog mode ,contents of the online redolog files are
copied to an archive area by an oracle background processes archiver (ARCn)there archive file
is know as archived redolog files,archived redologs or simply archived redo

-->These files are sometimes referred to as the offline redolog files since they are not open
during normal opertaion of the database and are required only during recovery.

-->The redolog files(online and archived)are essential for database recovery since they contain
information on all changes  made to the databse.

-->If the database is chosen to operate in noarchivelog mode online backups and database recovery
will not be possible

  To convert the database into archivelog mode

Step 1: shutdown the database
sys>>shutdown immediate;

Step 2: Edit the pfile and add the parameter

  $cd $ORACLE_HOME/dbs
  
   log_archive_dest=/disk1/oradata/ORCL/arch
  
   :wq  (save and quit)
  
Step 3: Create the folder with name arch

   $mkdir -p /disk1/oradata/ORCL/arch

Step 4 : Check the archivelog status

  sys>>startup mount;

Check the archive log list status :

 
  sys>>archive log list;
  sys>> select log_mode from v$database;

  if the status noarchivelog_mode type the below command

  sys>>alter database archivelog;

Step 5: Open the Database

  sys>>alter database open;


 for more info check the  Data dictionary views

  v$ARCHIVED_LOG
  v$ARCHIVE_DEST
  v$ARCHIVE_PROCESSES