miércoles, 26 de junio de 2013

Image copy backup using RMAN

Backup Set:
 A standard RMAN backup set contains one or more backup pieces, and each of these pieces consists of the data blocks for a particular datafile stored in a special compressed format. When a datafile needs to be restored, therefore, the entire datafile essentially needs to be recreated from the blocks present in the backup piece.

Image Copy:
An image copy of a datafile, on the other hand, is much faster to restore because the physical structure of the datafile already exists. Oracle 10g now permit image copies to be created at the database, tablespace, or datafile level through the new RMAN directive BACKUP AS COPY. For example, here is a command script to create image copies for all datafiles in the entire database:
# Set the default channel configuration. Note the use of the
# %U directive to insure unique file names for the image copies
# Create an image copy of all datafiles in the database

 why dont the client wants to have backupsets rather
than image copies? I know that Oracle first perfers to the image copies
compare to incremental or backupsets.

But, you know, image copy is just a block to block copy, no compression. It
would take good considerable time to finish the backup.

10g RMAN has very rich features, like BTC, binary compression and etc.

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