The RMAN executable, usually named rman, is the program that manages all backup and recovery
operations. You interact with the RMAN executable to specify backup and recovery operations you
want to perform.
You don't need an extra license for RMAN; it comes as a standard utility
included with an Oracle 8.0.x, Oracle8i, or Oracle9i installation.
The executable then interacts with the target database, starts the necessary server processes, and
performs the operations that you requested. Finally, the RMAN executable records those operations
in the target database's control file and the recovery catalog database, if you have one.
1.2.2 Server Processes
RMAN server processes are background processes, started on the server, used to communicate
between RMAN and the databases. They can also communicate between RMAN and any disk, tape,
or other I/O devices. RMAN server processes do all the real work for a backup or restore operation,
and a typical backup or restore operation results in several server processes being started.
Server processes are started under the following conditions:
• When you start RMAN and connect to your target database
• When you connect to your catalog -- if you are using a recovery catalog database
• When you allocate and open an I/O channel during a backup or recovery operation
1.2.3 Channels
A channel is an RMAN server process started when there is a need to communicate with an I/O
device, such as a disk or a tape. A channel is what reads and writes RMAN backup files. Any time
you issue an RMAN allocate channel command, a server process is started on the target database
server. It is through the allocation of channels that you govern I/O characteristics such as:
• Type of I/O device being read or written to, either a disk or an sbt_tape
• Number of processes simultaneously accessing an I/O device
• Maximum size of files created on I/O devices
• Maximum rate at which database files are read
• Maximum number of files open at a time
评论0