No archive log mode:
Running a database in noarchivelog mode means that redo logs would not be archived;LGWR(Log reade and writer) reuses filled groups without archiving.
Advantages:
Backup are small without posing any risk to disk space utilization.
Disadvantages:
NOARCHIVELOG mode can only protect database from instance failure and not from media failure.
Database can only be restored to the point of the most recent full database backups.
Online tablespaces backups cannot be taken
Only whole database backups can be used with noarchivelog mode.
Archivelog mode:
Running a database in archive log mode means that redo log would be archived. LGWR(Log read and writer) reuses filled groups after archiving.
Advantages:
Database recover is possible even in case of media failure
Point in time recoveries can be used. All transactions can be recovered in an event of database or any other failure.
Hot backups are possible.
Disadvantages:
You need sufficient disk space to archive redo logs.
Performance can be an issue.
If the database runs out of online redo logs then oracle stalls.
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