RMAN Restore and Recovery - Oracle RMAN for Absolute Beginners - page 160

Restoring Tablespaces While the Database Is in Mount Mode
Usually when performing a restore and recovery, DBAs will shut down the database and restart it in mount mode in
preparation for performing the recovery. Placing a database in mount mode ensures that no users are connecting to
the database and that no transactions are transpiring.
Also, if you're restoring and recovering the SYSTEM tablespace, then you must start the database in mount mode.
Oracle doesn't allow for restoring and recovering the SYSTEM tablespace data files while the database is open. This
next example restores the SYSTEM tablespace while the database is in mount mode:

$ rman target /
RMAN> shutdown immediate;
RMAN> startup mount;
RMAN> restore tablespace system;
RMAN> recover tablespace system;
RMAN> alter database open;

If successful, the last message you should see is this:

Statement processed

Restoring Read-Only Tablespaces
RMAN will restore read-only tablespaces along with the rest of the database when you issue a RESTORE DATDABASE
command. For example, the following command will restore all data files (including those in read-only mode):

RMAN> restore database;

Prior to Oracle 11g, you were required to issue RESTORE DATABASE CHECK READONLY to instruct RMAN to restore
read-only tablespaces along with tablespaces in read-write mode. This is no longer a requirement in Oracle 11g and
higher.

■ If you are using a backup that was created after the read-only tablespace was placed in read-only mode,
then no recovery is necessary for the read-only data files. In this situation no redo has been generated for the read-only
tablespace since it was backed up.

Note

Restoring Temporary Tablespaces
Starting with Oracle 10g, you don't have to restore or re-create missing locally managed temporary tablespace temp
files. When you open your database for use, Oracle automatically detects and re-creates locally managed temporary
tablespace temp files.
When Oracle automatically re-creates a temporary tablespace, it will log a message to your target database
alert.log such as this:

Re-creating tempfile <your temporary tablespace filename>