AIX Concurrent I/O for Oracle archive logs

  • From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
  • To: "oracle-l@xxxxxxxxxxxxx" <Oracle-L@xxxxxxxxxxxxx>
  • Date: Tue, 25 May 2010 09:06:12 -0700

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 
containing 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 
heavily, 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.

Thanks,
Brandon



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