Advantages of using RMAN in a 24x7 environment
What is the main advantage of using RMAN in a 24x7 operating system?
RMAN can be used in a 24x7 environment to perform hot backups. But hot
backups were possible long before RMAN. So why use RMAN to perform hot
backups? There are a couple of main reasons. If you are not using RMAN
for your hot backups, you have to place tablespaces in BACKUP mode
before you can begin to make a backup of that tablespace's datafiles.
When you place a tablespace in BACKUP mode, all changes that occur to
the tablespace are logged differently in the online redo logs than
under normal operating conditions. This can cause an increase in the
volume of information written to the online redo logs. RMAN does not
have this same issue to deal with. RMAN performing a hot backup does
not cause an increase in online redo log volume during the backup
RMAN can also help with incremental backups. The old backup scripts in
use cannot perform incremental backups. This can save considerable time
in your backup window.
There are many other advantages to RMAN as well. I would recommend
reading a book titled "Oracle9i RMAN backup & recovery" by Robert
Freeman on Oracle Press as well as the Oracle documentation.
This was first published in May 2004