An Oracle database can run in one of two modes. By default, the database is created in NOARCHIVELOG mode. Oracle Database lets you save filled groups of redo log files to one or more offline destinations using its ARCH process, known collectively as the archived redo log, or more simply the archive log. The process of turning redo log files into archived redo log files is called archiving.
When in NOARCHIVELOG mode the database runs normally, but there is no capacity to perform any type of point in time recovery operations or online backups. Thus, you have to shutdown the database to back it up, and when you recover the database you can only recover it to the point of the last backup. While this might be fine for a development environment, the big corporate types tend to frown when a weeks worth of current production accounting data is lost forever. We can check the status of the archiving mode of a database suing hte following query:
SQL> archive log list;SQL> select log_mode from v$database;
we can also with the below commnad to find the process:
$ ps -ef|grep -i _arc
