Oracle 11g RMAN New Compression Type (ZLIB)

Oracle 11g RMAN New Compression Type (ZLIB)

RMAN had compression of backups in Oracle Database 10g to conserve network bandwidth. Third-party compression utilities provided faster alternatives to RMAN's own, but RMAN 10g compression provided some features that the third-party ones did not. For example, when RMAN 10g restored datafiles, it did not need to uncompress the files first. This approach offers significant bandwidth savings during restores.

Now in Oracle Database 11g, RMAN offers another algorithm, ZLIB, in addition to the previously available BZIP2. ZLIB is a much faster algorithm but it does not compress as much. However, it will not consume near as much CPU. Therefore if you need to reduce CPU consumption ZLIB compression can offer you some compression at a lower cost to the CPU. (Note that BZIP2 is the default in version 11.1.x; if you want to use the new ZLIB compression you will need to license a new option called Advanced Compression Option.)

To use ZLIB compression just set the RMAN configuration parameter:

RMAN> configure compression algorithm 'ZLIB' ;

To change it to BZIP2:

RMAN> configure compression algorithm 'bzip2';