Re: AIX Concurrent I/O for Oracle archive logs

  • From: patrick obrien <po04541@xxxxxxxxx>
  • To: "oracle-l@xxxxxxxxxxxxx" <Oracle-L@xxxxxxxxxxxxx>, Brandon.Allen@xxxxxxxxxxx
  • Date: Tue, 25 May 2010 12:29:26 -0700 (PDT)


I too use AIX CIO and have been for years, for performance enhancement 

I've used these archives to rebuild my dev environment so I too know 
these are good. 


--- On Tue, 5/25/10, Allen, Brandon <Brandon.Allen@xxxxxxxxxxx> wrote:

From: Allen, Brandon <Brandon.Allen@xxxxxxxxxxx>
Subject: AIX Concurrent I/O for Oracle archive logs
To: "oracle-l@xxxxxxxxxxxxx" <Oracle-L@xxxxxxxxxxxxx>
Date: Tuesday, May 25, 2010, 9:06 AM


Hi List, 
Can anyone think of a good reason why Oracle’s archived redo logs shouldn’t be 
placed on a non-buffered (concurrent or direct IO) file system?  Oracle Support 
document 418714.1 specifically states NOT to use DIO/CIO for file systems 
 archive logs.    However, I have one AIX system where my archive logs have 
been on a file system mounted with CIO for years and I’ve never had any 
problems (and yes, I’ve successfully used the logs for actual recovery). 
I’m considering moving another of my systems to CIO because on the other 
system, when archive log backups run, the AIX file system cache gets flooded by 
the archive logs and it has recently started causing the OS to start paging 
 which in turn is bringing the system to a screeching halt for a few minutes, 
so I think if I move the logs to a CIO file system then they should no longer 
be read into the AIX buffer cache, and that should prevent this problem, but I 
just want to see if anyone
 has any good reasons why I should avoid using CIO with archive logs. 

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