Kevin Kempf's Blog

September 9, 2009

11gR2 RMAN: You are too dumb to pick a compression algorithm

Filed under: 11g, Oracle, RMAN — kkempf @ 9:57 am

OK, that’s being a little harsh, but as of 11.2 RDBMS, the old configure compression algorithm parameter has been dumbed down.

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;
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2 Comments

  1. Thats very good to know… thanks

    Comment by Kelli Garner — September 30, 2009 @ 5:07 pm

  2. I usually don’t post on Blogs but ya forced me to, great info.. excellent! … I’ll add a backlink and bookmark your site.

    Comment by Tnelson — September 30, 2009 @ 9:32 pm


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