Databases Reference
In-Depth Information
Backing Up Only Those Files Previously Not Backed Up
Problem
You want to create a backup of only new files that have been recently added or those files that failed to get backed up
during the normal backup schedule.
Solution
You can limit RMAN to backing up only specific files using the
not backed up
or
since time
clause within a
backup
command. Using the
not backed up
clause, you can instruct RMAN to back up only those data files or archived log
files that were never backed up previously. Here's the
backup
command that shows how to back up only previously
backed-up files:
RMAN> backup database not backed up;
Starting backup at 12-SEP-12
using channel ORA_DISK_1
skipping datafile 1; already backed up on 12-SEP-12
skipping datafile 2; already backed up on 12-SEP-12
skipping datafile 3; already backed up on 12-SEP-12
skipping datafile 4; already backed up on 12-SEP-12
skipping datafile 5; already backed up on 12-SEP-12
skipping datafile 6; already backed up on 12-SEP-12
skipping datafile 7; already backed up on 12-SEP-12
Finished backup at 12-SEP-12
Starting Control File Autobackup at 12-SEP-12
piece handle=/u01/app/oracle/fast_recovery_area/ORCL/autobackup/2012_09_12/o1_mf_n_793808685_
851rcxnt_.bkp comment=NONE
Finished Control File Autobackup at 12-SEP-12
RMAN>
You can also use the
not backed up
command with additional specifications such as the number of backups.
The following example shows how to back up only those archived redo logs that were backed up less than twice
on tape:
RMAN> backup device type sbt archivelog all not backed up 2 times;
RMAN considers only backups created on identical device type as the current backup when counting the number
of backups it has already made. Thus, the
not backed up
clause is ideal for specifying the number of archived redo
logs to be stored on a specific type of media. The previous example specifies RMAN to keep at least two copies of
archived redo logs on
tape.
How It Works
The
backup...not backed up
command comes in handy when you add one or more new files and want to ensure
that the new file's contents are backed up soon rather than waiting for the regular scheduled time for backup.
If you're making backup sets (instead of image copies), RMAN considers the completion time for any file in
the backup set as the completion time for the entire backupset. That is, all files in a backup set must have the same
