zt：Different type of RMAN backup compression in 11G

http://www.itpub.net/viewthread.php?tid=829560&pid=10201894&page=1&extra=#pid10201894

主題: Different type of RMAN backup compression in 11G
文件 ID: 註釋:427581.1 型別: REFERENCE
上次修訂日期: 31-JUL-2007 狀態: REVIEWED
In this Document
Purpose
Different type of RMAN backup compression in 11G
--------------------------------------------------------------------------------
Applies to:
Oracle Server - Enterprise Edition - Version: 11.0
Information in this document applies to any platform.
Purpose
In addition to the existing BZIP2 algorithm for binary compression of backup in oracle 10G, RMAN 11G executable also support ZLIB algorithm for the compress backup.ZLIB is the default compression for RMAN in 11G
Different type of RMAN backup compression in 11G
RMAN support binary compression of backup sets.You can choose which compression algorithm that RMAN uses for backups.By default, RMAN uses ZLIB compression.
ZLIB Compression is very fast but compression ratio is not as good as other algorithm.
BZIP2 Compression ratio is very good but is slower than ZLIB
If the COMPATIBLE initialization parameter is set to 11.0 or higher , then the default compression for RMAN backups is ZLIB. IF the COMPATIBILITY initialization parameter is set lower than 11.0 and greater than 10.2 then the default and only possible compression algorithm is BZIP2
Compression can be used for backupset of datafile, archive log and controlfiles.
e.g
RMAN> backup as compressed backupset archivelog all;
RMAN> backup as compressed backupset database;
RMAN> backup as compressed backupset current controlfile;
RMAN compress the backupset contents before writing to disk.No extra decompression steps are required during recovery for rman compressed backup;
To configure the compression algorithm
CONFIGURE COMPRESSION ALGORITHM '';
--------------------------------------------------------------------------------
Help us improve our service. Please email us your comments for this document. .

[@more@]