Why does a 11.2 database created the redo logs with a blocksize of 512? How to verify that?

LindaC
LindaC used Ask the Experts™
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Hi experts:

Why does a 11.2 database created the redo logs with a blocksize of 512, when you can see that the filesystems blocksize are 4096? How to verify why this was created in this way?

-oracle:/home/oracle> lsfs -q /dev/oemlv_red1
Name            Nodename   Mount Pt               VFS   Size    Options    Auto Accounting
/dev/oemlv_red1 --         /claroproem/REDO1      jfs2  6291456 rw         yes  no
  (lv size: 6291456, fs size: 6291456, block size: 4096, sparse files: yes, inline log: no, inline log size: 0, EAformat: v1, Quota: no, DMAPI: no, VIX: yes, EFS: no, ISNAPSHOT: no, MAXEXT: 0)
-oracle:/home/oracle> exit


SQL> SELECT BLOCKSIZE FROM V$LOG;

 BLOCKSIZE
----------
       512
       512
       512
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Most Valuable Expert 2012
Distinguished Expert 2018
Commented:
That is just the blocck size Oracle picked for it's redo logs.  I'm not sure you have control over that.

There is a great explaination of the datafile and redo block sizes here:
http://www.rampant-books.com/art_sharma_redo_log_blocksize.htm

Commented:
512 is the default blocksize for redo logs.

Copy/paste from Oracle

http://docs.oracle.com/cd/E14072_01/server.112/e10595/onlineredo002.htm

"Unlike the database block size, which can be between 2K and 32K, redo log files always default to a block size that is equal to the physical sector size of the disk. Historically, this has typically been 512 bytes (512B)."

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Commented:
Thanks for the documentation.

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