While the database is open, the following files can be backed up:
All datafiles
All archived redo log files
One control file, via the alter database backup controlfile
The server parameter file (SPFILE)
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Chapter 11: Backup and Recovery Options 395
NOTE
RMAN automatically backs up the control file and SPFILE whenever
the entire database or the SYSTEM tablespace are backed up.
Online backup procedures are very powerful for two reasons. First, they provide full point-intime
recovery. Second, they allow the database to remain open during the file system backup.
Even databases that cannot be shut down due to user requirements can still have file-system
backups. Keeping the database open also keeps the System Global Area (SGA) of the database
instance from being cleared when the database is shut down and restarted. Keeping the SGA
memory from being cleared will improve the database??™s performance because it will reduce the
number of physical I/Os required by the database.
NOTE
You can use the flashback database option, introduced in Oracle
Database 10g, to roll the database backward in time without relying
on physical backups. To use the flashback database command,
you must have a Flash Recovery Area defined, be running in
ARCHIVELOG mode, and must have issued the alter database
flashback on command while the database was mounted but not
open. Logs written to the Flash Recovery Area are used by Oracle
during the flashback database operation.
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