11. In your SQL*Plus session, rerun the query from Step 1 and note the difference
in usage.
Two-Minute Drill
Create Consistent Database Backups
• If the database is in noarchivelog mode, then whole consistent backups (full
or incremental) are the only type of backup possible.
• An RMAN-consistent backup is taken with the database in mount mode,
following a clean shutdown.
Back Up Your Database Without Shutting It Down
• An open backup of the database must also include a backup of the archivelog
files, either included in the same backup set or in a separate backup set.
• Open backups, for which the database must be in archivelog mode, can be
whole or partial, full or incremental.
Create Incremental Backups
• A level 1 incremental or cumulative backup cannot be based on a full backup,
only a level 0 incremental backup.
• Unless block change tracking is enabled, an incremental backup must scan the
entire database.
• An RMAN backup set, whether full or incremental, never includes unused
blocks.
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Automate Database Backups
• Oracle Enterprise Manager (Database Control or Grid Control) can schedule
the running of backup jobs.
Manage Backups, View Backup Reports, and
Monitor the Flash Recovery Area
• The LIST command shows what backups have been made, and the REPORT
command shows what backups are needed or are redundant.
• The flash recovery area is the default destination for RMAN disk backups.
• RMAN can automatically delete files considered to be obsolete from the flash
recovery area.
Define, Apply, and Use a Retention Policy
• The backup retention policy may be based on redundancy (keeping a certain
number of copies) or recovery window (guaranteeing the possibility of point-
in-time recovery).
• Backups considered obsolete according to the retention policy can be
automatically deleted.
Create Image File Backups
• An image copy is identical to the source file.
• Image copies can be directed only to disk.
• Image copies can be made of datafiles, the controlfile, and archivelog files.
Create a Whole Database Backup
• A whole RMAN backup is the full set of datafiles, the spfile, and the controlfile.
• RMAN does not back up online logs, tempfiles, or the password file.
Enable Fast Incremental Backup
• Changed blocks are tracked by the change tracking writer process, the CTWR.
• The change tracking file is automatically managed; the DBA can choose only
its name and location.
Create Duplex Backups and Back Up Backup Sets
• The COPIES keyword instructs RMAN to create multiple copies of backup sets
or images.
• Backup sets can be backed up into more backup sets with BACKUP BACKUPSET.
• The BACKUP RECOVERY AREA and BACKUP RECOVERY FILES commands
can only write to a tape destination.
Create an Archival Backup for Long-Term Retention
• The KEEP keyword creates a backup to which the retention policy will not be
applied.
• If the archival backup is an open backup, all necessary archive logs will be
automatically included.
Create a Multisection, Compressed,
and Encrypted Backup
P AR T III
• The SECTION keyword lets multiple channels back up one file concurrently.
• Backup sets can be compressed (unlike image copies), by default with the
BZIP2 algorithm.
• Encryption can be enabled using either a wallet or a password.
Report on and Maintain Backups
• RMAN will automatically delete backups from the flash recovery area
considered to be obsolete, if the flash recovery area is full.
• The DELETE OBSOLETE command will delete all backups considered
obsolete, whether in the flash recovery area or not.
Configure Backup Settings
• RMAN’s default behavior is modified with the CONFIGURE command.
• Configured defaults are stored in the target database’s controlfile, as part of
the RMAN repository.
Allocate Channels to Use in Backing Up
• Channels are of type disk or SBT (or SBT_TAPE). SBT channels are only
available if a suitable device driver has been installed.
• Parallelize backups by launching multiple channels, using ALLOCATE
CHANNEL commands within a run block or by configuring a default.
Configure Backup Optimization
• Optimization only applies to identical files: archivelogs, or datafiles that are
either offline or read-only.
• Optimization is not enabled by default, and if enabled is reliant upon the
retention policy currently in effect.
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Self Test
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