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RE: RAC and ASM disk layout

From: Kevin Closson <>
Date: Sun, 11 Jun 2006 10:00:30 -0700
Message-ID: <>


>>>Even if a lot a people think that ASM is a "black box", it
>>>is a great tool...and if you know the way how it works, and
>>>configure it correctly, you can make your life much easier.

Most people know that I am all about choice. The ability to choose the right technology for the right problem is a prime ingredient in IT success--no doubt.

Could someone humeor me with the answer to a couple of questions though? For instance, who on this list thinks they actually know how ASM works? I mean HOW IT WORKS? Ever seen a copy of osm.h? I have, right alongside odm.h since both headers are handiwork of the same developer at Oracle. The point I'm making here is that the technology is too new for anyone to say they know how it works. The cost based optimizer has been in Oracle for about 13 years. Who outside of building 400 at Oracle HQ knows how CBO works ( other than Jonathan Lewis)? I see it as absolutely maniacal to adopt brand new **optional** technology that changes the most fundamental
aspect of the Oracle database--how the database is stored. Think about it folks. This is technology that wasn't even used in an audited TPC benchmark for approximately 1 year after its production release. Odd!

Simpler? How many "filesystems" do the ASM crowd want? Start counting the things you can't do with'll take a while.

Of course the crown jewel of madness is ASM on NAS. NAS has an embedded OS, Volume Manager and Filesystem (WAFL, PolyServe, etc). On that you create preallocated files and add then as "disks" to ASM diskgroups. Madness!

Received on Sun Jun 11 2006 - 12:00:30 CDT

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