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RMAN Backup Compression - Am I using Advanced Compression

611900
611900 Member Posts: 225
edited May 1, 2011 7:55PM in Advanced Compression
Hello I want to confirm one thing -

I have 11.1.0.7 database and when I look at the setting of RMAN Compression by using "SHOW ALL" it shows me result like this -

CONFIGURE COMPRESSION ALGORITHM 'BZIP2'; # default
CONFIGURE DEVICE TYPE 'SBT_TAPE' PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;

My question is, If I am using COMPRESSION ALGORITHM 'BZIP2' in 11.1.0.7 database does it mean that I am using Oracle Advanced Compression option?

or this is a native compression option by oracle which is free.


Thanks!
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Answers

  • 781417
    781417 Member Posts: 42
    edited May 1, 2011 6:19PM
    bzip2 is the native compression available in 11gr1, you are NOT using advanced compression
    If you were to use zlib as the compression algorithm, then you would require the advanced compression option.

    see http://download.oracle.com/docs/cd/B28359_01/backup.111/b28270/rcmconfa.htm#BRADV89466
  • 611900
    611900 Member Posts: 225
    Thanks Craig for the prompt reply.

    I have another 11.2 database and it's compression is set to -

    CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default

    Does it mean that "BASIC" is also the native comression and it defaults to BZIP2.

    May be value of LOW, MEDIUM and HIGH will be the Advanced Compression Option.

    Please confirm.

    Thanks!
  • 781417
    781417 Member Posts: 42
    edited May 1, 2011 6:42PM
    I'll be honest I don't know what compression algorithm is used by the BASIC setting in 11gR2, but I would assume it is BZIP2, and hence there is no cost to using the BASIC setting.
    Yes, if you choose LOW, MEDIUM or HIGH then you would need to purchase the advanced compression option

    see http://download.oracle.com/docs/cd/E11882_01/backup.112/e10642/rcmconfa.htm#CHDEHCEB
  • 611900
    611900 Member Posts: 225
    Yes, looks like we are good. Found one of the post by Kevin Kemph and he states -

    If you don’t have Advanced Compression, you set it to BASIC.

    If you do have Advanced Compression enabled, you can choose between HIGH, MEDIUM and LOW.

    In reality, these terms map out as follows:

    HIGH = unmodified BZIP2
    MEDIUM = ZLIB
    LOW = LZO
    BASIC = BZIP2

    What does this mean to the average person?

    If you’re not using advanced compression, or are already using bzip2 and you wish to continue to use compression, simply do one of the following

    configure compression algorithm basic;
    configure compression algorithm clear;

    If you are using advanced compression and have bzip2 or zlib set, you need to select a level before running backup to avoid an ORA- error:

    configure compression algorithm [high/medium/low];
    configure compression algorithm clear;

    Thanks Craig once again!
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