Database Reference
In-Depth Information
Figure 4-1.
RMAN architectural components
The following list describes the RMAN architectural components:
DBA:
Appears somewhat short and bald in the diagram, which isn't far from the truth
(in my case).
Target database:
The database being backed up by RMAN. You connect to the target
database with the RMAN command-line
TARGET
parameter (see the next section for
more details).
RMAN client:
The
rman
utility from which you issue
BACKUP
,
RESTORE
, and
RECOVER
commands. On most database servers the
rman
utility is located in the
ORACLE_HOME/bin
directory (along with all the other Oracle utilities, such as
sqlplus
and
expdp
).
Oracle server processes:
When you execute the
rman
client and connect to the target
database, two Oracle server background processes are started. The first default server
process interacts with the PL/SQL packages to coordinate the backup activities. The
secondary polling process occasionally updates Oracle data dictionary structures.
Channel(s):
The Oracle server processes for handling I/O between files being backed up
(or restored) and the backup device (disk or tape).
PL/SQL packages:
RMAN uses two internal PL/SQL packages (owned by
SYS
) to perform
B&R tasks:
DBMS_RCVMAN
and
DBMS_BACKUP_RESTORE.DBMS_RCVMAN
accesses information in
the control file and passes that to the RMAN server processes. The
DBMS_BACKUP_RESTORE
package performs most of RMAN's work. For example, this package creates the system calls
that direct the channel processes to perform B&R operations.
