Re: Oracle 10g on AIX 5.2 - i/o configuration

DA Morgan wrote:
> The flashback area is more than just PITR. It is also recovery to the
> SCN.
Ummm, you can recover to the SCN with RMAN... might want to check your memory on that one:
http://download-west.oracle.com/docs/cd/B14117_01/server.101/b10770/rcmsynta63.htm#1000334

> But more importantly it is a solution to finding backup tapes
> that, hopefully, were promptly shipped off-site for their protection.

We use Tivoli for our backup system. TSM always copies backs up to two tapes (for several reasons, not the least of which is the reality that magnetic tapes go bad). One tape goes off site promptly and the other always stays in the library. So I can recover/restore a database anytime using the on-site copy of the backups.

> My recommendation would be to dump OCFS, there is talk at Oracle about
> deprecating it as it was the solution for a problem that no longer
> exists. Move to RAW and ASM and any issues go away.

We're running Oracle Applications (11i) on RAC, so ASM and RAW are not options. first off, there are several hundred tablespaces and trying to set this up on RAW partitions would be an adminsitrative nightmare. It was relatively simple to move it onto OCFS. Secondly, ASM may become a choice in the future but it is not supported yet for 11i. Oracle only even began supporting 10g as the DB platform with version 11.5.9 -- but I'm almost sure they'd disown our support contract if we tried to use ASM now. And anyway, we're still running 11.5.8 -- which requires a 9i DB -- and doesn't have ASM.

I definitely agree that there are a lot of plusses for ASM -- in fact I personally would choose ASM over OCFS any day, all else being equal. But you and I both know that all else is *not* equal... especially when dealing with third parties. Some environments or applications (however braindead it might seem) may require a cooked filesystem. Currently if you want to use RAC that means you can either use OCFS or a supported third-party filesystem (e.g. sun's or veritas's).

And although I agree that ASM is the way to go if it's possible, I can't see Oracle "dumping OCFS" any time soon. I heard from Wim Coekaerts two weeks ago that "ocfs seems tobe used by like 50% of all linux/rac setups". It wasn't a statistical fact - it was just an offhand comment - but i'd say it's a far cry from "deprecating it as it was the solution for a problem that no longer exists".

> Our current best practice for RAC is to always have a flashback area.

Yeah, that makes sense. I'd probably do the same thing as long as OCFS v1 isn't in the picture.

Just out of curiousity, you know of any testing that's been done to determine the impact of the additional IO?

/js Received on Tue Jun 14 2005 - 12:37:57 CDT