4 Connecting to Databases with RMAN

Starting RMAN Without Connecting to a Database

You can start RMAN at the operating system command line without connecting to a database by issuing the RMAN command without any arguments. For example, enter:

% rman

If you did not specify the CMDFILE , SCRIPT or @ option at the command line, then RMAN displays the RMAN prompt:

RMAN>

After the RMAN prompt is displayed, you can issue further commands to connect to the target database, recovery catalog database, or auxiliary database.

If you start RMAN without specifying either CATALOG or NOCATALOG on the command line, then RMAN makes no recovery catalog connection. The first time a command is issued that requires the RMAN repository, RMAN performs the operation in NOCATALOG mode if you have not connected to a recovery catalog yet. After that point, the CONNECT CATALOG command can no longer be used without exiting and restarting the RMAN client.

Connecting to a Target Database and a Recovery Catalog

The following examples use the following sample connection data, and assume that a recovery catalog is being used.

% rman TARGET / CATALOG rman/cat@catdb

% rman TARGET SYS/oracle@trgt CATALOG rman/cat@catdb

% rman
RMAN> CONNECT TARGET /
RMAN> CONNECT CATALOG rman/cat@catdb

% rman
RMAN> CONNECT TARGET SYS/oracle@trgt 
RMAN> CONNECT CATALOG rman/cat@catdb

Connecting to an Auxiliary Database

To use the DUPLICATE command, you need to connect to an auxiliary instance. To perform RMAN TSPITR, you may also need to connect to an auxiliary instance if, for example, you do not let RMAN manage the auxiliary instance for you.

If the auxiliary instance uses a password file for authentication, then you can connect using a password for either local or remote access. If you are connecting remotely through a net service name, then authentication through a password file is mandatory.

The following dummy values have been substituted into the following examples:

% rman AUXILIARY SYS/aux@auxdb

% rman TARGET SYS/oracle@trgt AUXILIARY SYS/aux@auxdb CATALOG rman/cat@catdb 

% rman
RMAN> CONNECT AUXILIARY SYS/aux@auxdb

% rman
RMAN> CONNECT TARGET SYS/oracle@trgt
RMAN> CONNECT CATALOG rman/cat@catdb
RMAN> CONNECT AUXILIARY SYS/aux@auxdb

Diagnosing Connection Problems

When diagnosing errors RMAN encounters in connecting to the target, catalog and auxiliary databases, using SQL*Plus to connect to the databases directly can reveal underlying problems with the connection information or the databases.

RMAN> CONNECT target sys/oracle@target

SQL> CONNECT sys/oracle@target AS SYSDBA

Hiding Passwords When Connecting to Databases

If you create an RMAN command file which uses a CONNECT command with database level credentials (user name and password), then anyone with read access to this file can learn the password. There is no secure way to incorporate a CONNECT string with a password into a command file.

It is also possible, using the ps command under Unix or some similar command under other operating systems, to view command lines and arguments entered into the shell or other host operating system command line interpreter. Therefore, it is risky to invoke RMAN with a command line like this example:

% rman TARGET sys/oracle@target

To connect to RMAN from the operating system command line and hide authentication information, you can start RMAN without connecting to databases, and then enter CONNECT commands at the RMAN prompt. You can also start RMAN without a password in the connect string, as in this example:

% rman TARGET sys@target

RMAN will prompt for a password in such a case.

If you create an RMAN command file which uses a CONNECT command that includes authentication information, RMAN does not echo the connect string when you run the command file with the "@" command. This prevents connect strings from appearing in any log files that contain RMAN output.

For example, create a command file listbkup.rman which reads:

CONNECT target sys/oracle@target
LIST BACKUP;

Then execute this script by running RMAN with the @ command line option:

% rman @listbkup.rman

When the command file executes, RMAN replaces the connection string with an asterisk, as shown in the following output:

Recovery Manager: Release 10.2.0.1.0 - Production

Copyright (c) 1995, 2005, Oracle.  All rights reserved.

RMAN> connect target *
2> list backup;
3>
connected to target database: RDBMS (DBID=771530996)

using target database control file instead of recovery catalog

List of Backup Sets
===================
...rest of output omitted

Sending RMAN Output Simultaneously to the Terminal and a Log File

If you specify the LOG option at the command line, then RMAN displays command input but does not display the RMAN output. The easiest way to send RMAN output both to a log file and to standard output is to use the UNIX tee command or its equivalent on another operating system. For example:

% rman | tee rman.log
RMAN>

In this way, both input and output are visible within the RMAN command-line interface.

Using the RMAN Pipe Interface

The RMAN pipe interface is an alternative method for issuing commands to RMAN and receiving the output from those commands. With this interface, RMAN obtains commands and sends output by using the DBMS_PIPE PL/SQL package instead of the operating system shell. Using this interface, it is possible to write a portable programmatic interface to RMAN.

The pipe interface is invoked by using thePIPE command-line parameter for the RMAN client. RMAN uses two private pipes: one for receiving commands and the other for sending output. The names of the pipes are derived from the value of the PIPE parameter. For example, you can invoke RMAN with the following command:

% rman PIPE abc TARGET SYS/oracle@trgt

RMAN opens the two pipes in the target database: ORA$RMAN_ABC_IN, which RMAN uses to receive user commands, and ORA$RMAN_ABC_OUT, which RMAN uses to send all output back to RMAN. All messages on both the input and output pipes are of type VARCHAR2.

Note that RMAN does not permit the pipe interface to be used with public pipes, because they are a potential security problem. With a public pipe, any user who knows the name of the pipe can send commands to RMAN and intercept its output.

If the pipes are not already initialized, then RMAN creates them as private pipes. If you want to put commands on the input pipe before starting RMAN, you must first create the pipe by calling DBMS_PIPE.CREATE_PIPE. Whenever a pipe is not explicitly created as a private pipe, the first access to the pipe automatically creates it as a public pipe, and RMAN returns an error if it is told to use a public pipe.