Oracle OCP 1Z0-053(Rman Compression Algorithm)

abstractcyj發表於2016-03-24
OracleGo
53.You want to use RMAN to create compressed backups.
Which statement is true about the compression algorithms that RMAN can use?
A. The BZIP2 compression algorithm consumes more CPU resources than the ZLIB compression
algorithm.
B. The ZLIB compression algorithm consumes more CPU resources than the BZIP2 compression
algorithm.
C. The ZLIB compression algorithm provides maximum compression and produces smaller backups than
the BZIP2 compression algorithm.
D. Only the BZIP2 compression algorithm can be used to make compressed backups to disk.
Answer: A

BZIP2最大限度壓縮，ZLIB更節省CPU資源

參考：https://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmconfa.htm

Configuring the Backup Compression Algorithm

RMAN supports binary compression of backup sets. The supported algorithms are BZIP2 (default) and ZLIB. The BZIP2 algorithm is optimized for maximum compression, whereas the ZLIBalgorithm is optimized for CPU efficiency. BZIP2 consumes more CPU resource than ZLIB, but will usually produce more compact backups. The COMPATIBLE initialization parameter must be set to 11.0.0 or higher for ZLIB compression, which requires the Oracle Advanced Compression option.

You can configure the compression algorithm with the following syntax, where alg_name is a placeholder specifying either BZIP2 or ZLIB.

Example 6-2 Configuring the Backup Compression Algorithm 

CONFIGURE COMPRESSION ALGORITHM TO 'alg_name';

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