Database Reference
In-Depth Information
If you experience a media failure, you can restore all data files, as follows:
RMAN> shutdown immediate;
RMAN> startup mount;
RMAN> restore database;
After your database is restored, you can fully recover it:
RMAN> recover database;
RMAN> alter database open;
You're good to go, right? No, not quite. RMAN's default attributes are reasonably set for simple backup
requirements. The RMAN out-of-the-box settings may be appropriate for small development or test databases. But,
for any type of business critical database, you need to consider carefully where the backups are stored, how long
to store backups on disk or tape, which RMAN features are appropriate for the database, and so on. The following
sections in this chapter walk you through many of the B&R architectural decisions necessary to implementing RMAN
in a production environment. RMAN has a vast and robust variety of options for customizing B&R; and, typically,
you don't need to implement many of RMAN's features. However, each time you implement RMAN to back up a
production database, you should think through each decision point and decide whether you require an attribute.
Table
4-1
summarizes the RMAN implementation decisions and recommendations. Each of the decision points
in the table is elaborated on in subsequent sections. Many DBAs will have differing opinions concerning some of
these recommendations; that's fine. The point is that you need to consider each architectural aspect and determine
what makes sense for your business requirements.
Table 4-1.
Overview of Architectural Decisions and Recommendations
Decision Point
Recommendation
1. Running the RMAN client
remotely or locally
Run the client locally on the target database server.
Use
SYS
unless you have a security requirement that dictates otherwise.
2. Specifying the backup user
3. Using online or offline backups
Depends on your business requirements. Most production databases
require online backups, which means that you must enable archiving.
4. Setting the archive redo log
destination and file format
If you're using an FRA, archive logs are written there with a default format.
I prefer to use the
LOG_ARCHIVE_DEST_N
initialization parameter to
specifically set the location outside the FRA.
5. Configuring the RMAN backup
location and file format
Depends on your business requirements. Some shops require tape backups.
If you're using disk, place the backups in the FRA, or specify a location via
channel settings. I prefer not to use an FRA and to explicitly specify the
location and file format via a
CONFIGURE
command.
6. Setting the autobackup
of the control file
Always enable autobackup of the control file.
Either place it in the FRA, or con
figure
a location. I prefer to write the
autobackup of the control file to the same location as that of the
database backups.
7. Specifying the location of the
autobackup of the control file
(
continued
)
