Re: ASM diskgroup redundancy

From: Jörg Jost <>
Date: Mon, 19 Sep 2011 01:38:06 -0700 (PDT)
Message-ID: <>

On 18 Sep., 19:48, Mladen Gogala <> wrote:
> [...]
> Now, this is a perfectly reasonable explanation: ASM does for free what
> the storage manufacturer charges for: replication between 2 different SAN
> devices. Makes perfect sense. How are you satisfied with the performance?
> That, of course, means that the server CPU cycles are used for disk
> mirroring. Is it a big burden? The companies that I worked for have
> usually used external redundancy, provided by the SAN itself plus a
> standby database, usually in maximum performance mode, to minimize the
> impact on the primary. In one case, the standby replication went over WAN
> from Louisville, KY to NYC, NY. It did consume very significant
> communication resources, completely devouring a T2 line.

The performance of the disc subsystem makes no trouble at all. But i can not compare the performance to the alternative solution delivered
by the storage build in feature because of the mentioned reasons.

Oracle 11g is at least theoretical better in doing this than 10g. The feature called
preferred read failure group is very helpful for a configuration described above.
We have both versions in production, but the sides are so different that i can
not compare the numbers without comparing apples with pears.

And at Monty Python, i love them, i own the mentioned film on DVD and some
more, so thanks for recalling this, i have to look this film again :)


Joerg Received on Mon Sep 19 2011 - 03:38:06 CDT

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