Re: AIX Concurrent I/O for Oracle archive logs
- From: Nuno Souto <dbvision@xxxxxxxxxxxx>
- Date: Thu, 27 May 2010 17:36:13 +1000
Allen, Brandon wrote,on my timestamp of 27/05/2010 11:09 AM:
> Do you have any input regarding my specific question
> regarding archived logs - have you ever placed them
> on cio file systems, or can you think of any reason
> why it would be a problem? We're running 9i in this
> case so we have to mount the file systems with cio in
> order to use it.
Never. I've been on AIX 5.3l and 10gr2 for the last 3.5
years and before that on RHLinux where none of this
applies anyway! In AIX I use JFS2 non-CIO and let Oracle
do CIO or not, as needed. In your case - 9i - this
is of course not possible. Dang!....
But let's consider the IO that archived redo logs have:
almost always sequential, in bursts during an archive and
then a sequential read if you move/compress them to the
FRA with RMAN. I wouldn't class burst sequential IO as
stressful on locking at all so probably having the file
system mounted with/out CIO in that particular case will
amount to nothing? Assuming you're not doing extremes of
log miner or other random IO on the archived RL, I wouldn't
worry about the type of IO.
Of course: IMHO, YMMV, no animals harmed while testing this.
> Also, not sure if you've read this
> updated paper
> (http://public.dhe.ibm.com/partnerworld/pub/whitepaper/162b6.pdf)
> from Dennis Massanari, but it has some good information
> about using the newer, easier to manage, 64K large pages
> instead of the older 16MB large pages. I haven't tested
> them out yet, but am planning to soon.
> Have you had any experience with it yet?
Yes, I've seen the 64K notes. Excuse the non-believer
approach but to me "new" means "untested, unproven", no
matter how much IBM and/or Oracle mean "better".
Adn I can't for the life of me see why a 64K pagesize
would be "easier to manage" than a 16M one.
Yes, I'll try them at some future stage. Likely when we
move to AIX 6. Not now: I see no reason whatsoever to
move away from 16M pages, they do the job perfectly well
for my 40GB SGAs and work like a charm. I'll let someone
else iron out the bugs...
;)
--
Cheers
Nuno Souto
in wet Sydney, Australia
dbvision@xxxxxxxxxxxx
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