Re: asm vs raw - the smackdown

From: Jeremy Schneider <jeremy.schneider_at_ardentperf.com>
Date: Wed, 27 May 2009 13:00:21 -0500
Message-ID: <4A1D7FB5.6070407_at_ardentperf.com>

~Jeff~ wrote:
> does anyone know of any papers or study comparing ASM vs raw
> performance? We have a vendor deadset on raw, and the DbAs would
> rather not have to deal with that!

From metalink note 754305.1, accessed today: ==> In release 11.2, the Oracle installer and DBCA (Database configuration assistant) will no longer support raw/block devices for database files.
==> As stated in metalink note <578455.1>, Oracle plans to fully desupport RAW/Block device storage effective with the next major release following 11.2. At this time, customers will need to migrate any data files stored on RAW/Block devices to ASM, a cluster file system, or NFS. Thus, we recommend new databases not be deployed on RAW/Block devices.

I couldn't access metalink note 578455 but it is also mentioned here: http://askdba.org/weblog/?p=154

Also, just a technicality, but if you're on Linux then raw access has long been deprecated in favor of direct block access.

I wouldn't expect to see too much difference in performance since ASM is essentially accessing the devices in a "raw" manner. But there are countless other reasons to choose ASM above raw. And I really can't think of a single good reason to choose raw above ASM today. If it were me, I'd continue to strongly argue with the vendor.

-Jeremy

-- 
Jeremy Schneider
Chicago, IL
http://www.ardentperf.com

--
http://www.freelists.org/webpage/oracle-l

Received on Wed May 27 2009 - 13:00:21 CDT