Databases Reference
In-Depth Information
One may argue that since the control file can record all of RMAN's metadata, there is no need to create and
manage a separate recovery catalog database to store RMAN metadata. However, consider a situation where you
lose all your control file copies at once. You can, of course, rebuild the control file quickly using the output of a recent
alter database backup controlfile to trace
command. However, when you re-create the control file using the
output of that command, the one thing you do not get back is all the RMAN metadata that used to be stored in the
control file! This and the fact that Oracle may always overwrite even useful RMAN metadata in the control file means
you should seriously consider using the recovery catalog. Oracle recommends using a recovery catalog in order to
provide redundancy for your RMAN metadata. Chapter 6 discusses the recovery catalog in detail.
Starting the RMAN Client
Problem
You want to start working with the RMAN tool and need to use the RMAN client.
Solution
Invoke the RMAN executable, which is named
rman
, to start the RMAN client. The RMAN executable file is always in
the $ORACLE_HOME/bin directory. If you've set your ORACLE_HOME environment variable, you'll be able to invoke
RMAN from any directory by simply entering the command
rman
at the command prompt:
[oracle@virtual1 ~]$ rman
Recovery Manager: Release 12.1.0.0.2 - Beta on Tue Jul 24 10:41:54 2012
Copyright (c) 1982, 2012, Oracle and/or its affiliates. All rights reserved.
RMAN>
When the RMAN prompt is displayed, you aren't connected to a target database or the recovery catalog. You
must, of course, connect to the target database, the recovery catalog, or the auxiliary database (or sometimes all of
them) to perform backup and recovery tasks. Once you finish working with RMAN, you shut down the Recovery
Manager by using the command
exit
at the RMAN prompt:
RMAN> exit
Recovery Manager complete.
[oracle@virtual1 ~]$
You can also use the QUIT command to terminate your rman session, as shown here:
RMAN> quit
How It Works
The command
rman
starts the RMAN client. Once the RMAN prompt is displayed, you can choose to connect to
the target database, the recovery catalog, or an auxiliary database. If you issue any RMAN command at this stage,
RMAN will use the RMAN repository in the default nocatalog mode. You can't use the
connect catalog
command
to connect to the recovery catalog after having issued RMAN commands in the nocatalog mode—you must first exit
RMAN before you can restart and make a connection to the recovery catalog.
