Database Reference
In-Depth Information
Setting the
CONTROL_FILE_RECORD_KEEP_TIME
Parameter
When using RMAN without a recovery catalog (which we discuss in Chapter 5, “Recovering
Databases with RMAN”), you will need to make sure that you have set the
CONTROL_FILE_
RECORD_KEEP_TIME
parameter correctly. This parameter is used to determine how long
RMAN-related control-file records are maintained in the control file. Make sure this param-
eter is set high enough so that it will not interfere with your retention-policy requirements
(see the next section for more on retention policies).
You can set the
CONTROL_FILE_RECORD_KEEP_TIME
(defined in days) parameter using the
ALTER SYSTEM
command, as shown here:
-- Set control_file_record_keep_time to 14 days.
SQL> alter system set control_file_record_keep_time=14
This is a dynamic parameter; therefore, you can change it without having to shut down
the database.
Setting Retention Policies
RMAN
retention policies
are used to manage how long Oracle will maintain backups.
When you're using the FRA, retention policies are used for automated cleanup of unneeded
backup sets, which eliminates the need to manually manage space usage. When you're not
using the FRA, retention policies can be used to manually manage space usage. In the fol-
lowing sections, you'll learn about the two different kinds of retention policies and how to
configure them.
Types of Retention Policies
These are the different types of retention policies that you can set in RMAN:
■
None
■
Redundancy (the default)
■
Recovery window
Let's look at the redundancy and recovery window retention criteria in a bit more detail.
Then we will cover how to override the retention criteria with the
KEEP
operand.
ReDUNDANCY ReTeNTiON POliCY
The redundancy retention policy ensures that there will be a certain number of backups
available for recovery. Once a backup is no longer needed, Oracle will mark it as obsolete,
making it eligible for removal. For example, if the retention criterion is set to redundancy 2,
then the following happens as you back up your database:
Backup 1 occurs; when successful, it is considered current.
■
Backup 2 occurs. Backups 1 and 2 are considered current.
■
Backup 3 occurs. Backup 1 is marked as obsolete and backups 2 and 3 are considered
current.
■
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