10g - ASM 2004-05-11 - By Nuno Souto
-- -- Original Message -- --
From: "Koivu, Lisa " <Lisa.Koivu@(protected) >
>
> I question the whole idea in a SAN environment because the server I have
> to work with only has 2 controllers, and the SAN cache is going to skew
> any performance metrics gleaned from the i/o. =20
Well, here is another point of view:
In a SAN, you may well be sharing that huge cache with a number of other
"logical devices " (the LUNs) being used by all and sundry besides your
database. And not all SANs have cache partitioning. So, you may well find
that huge cache memory reduced to a vague recollection as far as your db
is concerned.
As such, it may well be desirable to rely on the db cache itself to even
things out. That means (along with a host of other options) that ASM may
indeed be a good idea for you. Just define the LUNs - mirrored or not
depends mostly on the conditions of your contract with the SAN
provider - to Oracle 's ASM and let it manage them and their space and how
well that space is cached in the Oracle cache. Which hopefully won 't
have a Windows network device hanging off it...
> Does that make sense or am I off my rocker?
Of course it does, but as usual: it "deep-ends "....
> Any suggestions are appreciated. =20
Well you got mine. Based on prior experience of using SANs in shared
environments, when ASM was not available. How much I longed for it...
Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision@(protected)
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