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Subject: DB Block size and JFS2
Date: 3 Mar 2006 03:53:21 -0800
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Hello people,

I would like here to ask you something about Oracle from the DBA point
of view if you don't mind.

The issue has to do with the Oracle DB_BLOCK_SIZE. (i am referring
specifically to AIX, but i think it applies to other OS also)
Based on the documentation i read so far i came to the following
conclusion:

If you are going to use JFS2 with CIO option then your DB_BLOCK_SIZE
should match the filesystem block size of your OS (in our case this is
equal to 4K).
If you are going to use raw devices you should not worry about this,
you can choose any block size (4K 8K 16K 32K).

Some documentations disagree with the above and say that if are using
bufferred I/O you should match the db_block_size with the filesystem
buffer size
and if you are using DIO or CIO it does not matter.

I would appreciate it a lot if you could comment on the above and let
me know of your opinion/experience.

Thanks