Wednesday, April 4, 2007

Recovery Manager: 01 general introduction

Recovery Manager is the Oracle utility that can manage all of your Oracle backup and can help you to perform recovery.
Yes, I know your scripts are still working and will continue to work, but what about the benefits that RMAN comes with ?

With RMAN you can perform activities that are not available with your scripts...
I mean incremental backups... with RMAN you can copy data blocks that have changed since the last backup and those only;
I mean true parallelization of your backups, just granted configuring and using I/O channels;
I mean compressed backup set compared with image copies, how much space on your file system will you save ?;
I mean no extra redo log generation during online backups;
I mean detection of corrupt blocks during backups;
I mean REPORT and LIST commands to know what backup are available...;
I mean stored catalog RMAN scripts to automize your backup... yes just like your shell scripts!!!.

The RMAN environments is composed by:
1) the rman utility;
2) background server processes started by RMAN when you connect to the target database, or
when you connect to the recovery catalog database or when you use I/O channels;
3) the I/O channel, a server process useful to read and write the RMAN backup;
4) the target database, namely the database that you want backup or recovery;
5) the recovery catalog database, an optional database used to maintain and preserve backup and recovery informations executed on the target database. Note that the recovery catalog database preserves only information about the backups and recoveries of the target database and not the physical backup files themselves. In the recovery catalog database you can also save your RMAN scripts. Every single catalog schema is about 200 MB;
6) the media management layer, useful to manage datas to and from tape, provided by third-party company;
7) the backup set, logical collection of files associated with a backup, composed of one or more physical file called backup pieces.

Click here to read the next step.

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