Re: ASM and RAID

From: Robert Klemme <>
Date: Sun, 21 Dec 2008 18:23:11 +0100
Message-ID: <>

On 18.12.2008 17:32, Michael Austin wrote:
> ASM also does not do the actual reading/writing - the RDBMS does. In
> other words - ASM does not proxy the I/O for the RDBMS - RDBMS writes
> directly to the data files. ASM just tells the RDBMS what the extent
> map is and only at file open time... which is why you need additional
> shared_pool (1MB for every 100GB of file space).

That's an interesting bit of information. How is the ASM able to replace a clustered file system? Does it provide only the meta data layer which controls concurrent access to files?

> There is a book called Automatic Storage Management - practical
> under-the-hood ??? that is very good at the mechanisms within ASM and
> RDBMS...
I am assuming you mean this one:

Kind regards

        robert Received on Sun Dec 21 2008 - 11:23:11 CST

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