CIO & flash recovery area

  • From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 17 Apr 2006 08:58:47 -0700

Howdy list,
 
Oracle support can't answer this question, so I'm turning to y'all.  I'm 
setting up a new 10.2.0.2 database on AIX 5.3 and have set 
filesytemio_options=setall in order to enable CIO (concurrent I/O) on the 
datafiles, and I have mounted the filesystems for the redologs with cio and 
agblksize=512.  All good there.  My question is on how to configure the 
filesystem for the flash recovery area - should it also be mounted with cio and 
agblksize=512?  I'm thinking cio would be good for this filesystem since the 
same blocks aren't likely to be accessed repeatedly, there is no point in 
keeping them in the filesystem buffer cache, right?  Regarding the setting of 
agblksize,  I think it depends on the I/O size Oracle uses to access the files 
in the flash recovery area (flashback database log, archived redo logs, 
datafile copies, etc.).  I'm guessing that archive logs are written in 512 byte 
blocks just like the online redo, but I don't know if that's true or not.  Do 
any of you know?  Is anyone else running your flash recovery area on CIO - what 
have your experiences been?
 
Thanks,
Brandon
 
 

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