Recovery Manager Advanced Techniques - Oracle 10g/11g Data and Database Management Utilities - page 84

In this chapter, we will be looking at methods to administer the Recovery
Manager and to optimize the backup task. This will include backup multiplexing,
configuration of a recovery catalog, performing backup in compressed mode,
enabling backup compression, and the compression algorithms. We will also
be looking the process of performing an intra-file parallel backup, reducing the
performance impact of performing a backup, cloning a database on the fly, using
Recovery Manager to migrate a database to a different platform, and finally,
migrating the database to an ASM environment.
Recovery Manager basics
Recovery Manager ( RMAN ) is a tool that efficiently and reliably performs backup,
restoration, and recovery tasks on Oracle Databases. It can be used from a Command
Line Interface ( CLI ) or from the Enterprise Manager Web Console. It is still available
in 10g from the Enterprise Manager Java Console. However, its usage is discouraged
as this console has become obsolete and it is no longer available in 11g.
RMAN is a utility that works in a client-server fashion when launched in CLI mode,
or in a three-tier fashion when launched from the EM Console. It commands actions
from the client side and the entire backup and restore operations take place on
the server side using the server storage resources. The database to be managed is
known as the TARGET database. RMAN may optionally use a database to keep
track of the backups. This database is known as the recovery catalog database, and
is an independent database that stores information about the backup operations for
different databases. This database shouldn't reside on the same server as the target
database, and this database must have its own backup strategies. It is a good practice
to perform the RMAN operations using a recovery catalog database, as this not only
provides longer backup records, leveraging the target database control file from
storing this information, but it can also be used to store frequently used
RMAN scripts.
The backups can be stored on a server-side attached disk system, or if available,
they can be stored on tape. A certified tape unit must be configured properly and
for it to properly work with the RMAN script, a third party must supply the Media
Management Library ( MML ).