RMAN Backups and Reporting - Oracle RMAN for Absolute Beginners - page 133

■ the rMaN incremental level 0 backups are used to restore the data files, whereas the rMaN incremental
level 1 backups are used to recover the data files.

Note

When using incremental backups, I almost always use the default, of differential. Usually, I don't worry about the
differences between differential and cumulative backups. If you require cumulative backups, you must specify the key
word CUMULATIVE . Here is an example of taking a cumulative level 1 backup:

RMAN> backup incremental level=1 cumulative database;

Here are some examples of taking incremental backups at a more granular level than the database:

RMAN> backup incremental level=0 tablespace sysaux;
RMAN> backup incremental level=1 tablespace sysaux plus archivelog;
RMAN> backup incremental from scn 4343352 datafile 3;

Making Incrementally Updating Backups
The basic idea behind an incrementally updating backup is to create image copies of data files and then use
incremental backups to update the image copies. In this manner, you have image copies of your database that are kept
somewhat current. This can be an efficient way to combine image copy backups with incremental backups.
To understand how this backup technique works, you'll need to inspect the commands that perform an
incrementally updating backup. The following lines of RMAN code are required to enable this feature:

run{recover copy of database with tag 'incupdate';
backup incremental level 1 for recover of copy with tag 'incupdate' database;}

In the first line a tag is specified (this example uses incupdate ) . You can use whatever you want for the tag
name; the tag name lets RMAN associate the backup files being used each time the commands are run. This code will
perform as follows the first time you run the script:
• RECOVER COPY generates a message saying there's nothing for it to do.

BACKUP INCREMENTAL creates an image copy of the • If no image copies exist, the

database data files.
You should see messages such as this in the output when the RECOVER COPY and BACKUP INCREMENTAL commands
run the first time:

no copy of datafile 1 found to recover
...
no parent backup or copy of datafile 1 found
...

The second time you run the incrementally updating backup, it does as follows:

RECOVER COPY again generates a message saying it has nothing to do. •

BACKUP INCREMENTAL makes an incremental level 1 backup and assigns it the tag name
specified; this backup will subsequently be used by the RECOVER COPY command.

•