Databases Reference
In-Depth Information
How It Works
You can make a backup of the archived redo logs using any of the following clauses with the
backup
command:
archivelog all
•
plus archivelog
•
archivelog from...
When you issue the
backup
command with the
archivelog all
or
plus archivelog
clause, either of these
commands will back up the archived redo logs, and RMAN first directs the database to switch the current online redo
log group. After this, all unarchived redo logs, including the one the database just switched out of, are archived.
This process guarantees that the backup contains all the redo information generated until the backup started.
When you use the
backup database plus archivelog
command to back up archive logs as part of another
backup, RMAN will perform the following operations in the sequence listed here:
•
Run the
alter system archive log current
command.
1.
Run the
backup archivelog all
command.
2.
Back up the rest of the data files specified by the
backup database
command.
3.
Run the
alter system archive log current
command.
4.
5.
Back up the new archive logs generated during the backup operation.
The sequence of operations listed here means that RMAN will have all the necessary archived redo log
information it'll need down the road if it has to perform a complete recovery of the database.
Not
■
the
backup database plus archivelog
command will back up the entire database and all the archived redo
logs as well as the current control file in a single command. see the next recipe for details.
Instead of backing up archive logs specifically by using the
backup archivelog
command, you can back up the
archive logs as part of a database backup or some other data file backup. The following recipe shows how you can
back up the database, along with all the archive logs, using a single command,
backup database plus archivelog
.
Backing Up Everything
Problem
You want to create a backup of the entire database, meaning all the data files, the archived redo logs, and the control file.
Solution
To make sure the control file is backed up automatically as part of the database backup, first make sure you have
configured automatic control file backups by using the following command:
RMAN> configure controlfile autobackup on;
old RMAN configuration parameters:
CONFIGURE CONTROLFILE AUTOBACKUP ON;
