Re: ASM diskgroup redundancy

From: Jörg Jost <>
Date: Mon, 19 Sep 2011 03:57:44 -0700 (PDT)
Message-ID: <>

On 19 Sep., 12:16, Noons <> wrote:
> > Now you have the choice, use the ASM mirroring feature to make all
> > mirroring over both
> > storages or use some build in feature delivered by the storage
> > manufacturer. Last one will
> > often cause expensive investments, because this feature is not cost
> > free.
> And ASM does the mirroring out of what?  Thin air?  Doesn't it need a high speed
> interconnect, just like the storage replication does?  It's not included in the
> cost of Oracle...
> Sorry, but I don't see why ASM has to be cheaper when it needs the same high
> performance hardware connection as the storage.
> And please, don't anyone jump in and tell me that ASM is "highly optimized": it
> isn't, and that is NOT what I am talking about.

As i said, the feature to mirroring data over two storage devices is not for free. At
least not by every manufacturer. Of course inside one device, mirroring is build in.
And of course you have to connect the two devices over fast connections.

All what this discussion is about is mirroring the writing of the database server
processes to another SAN. Oracle writes only to one target, but for security reasons
you need the changed blocks on another SAN located anywhere.

So the only cost difference lies in the money you have to spend for the mirroring feature
to the storage manufacturer. Costs for hardware including network devices is the same
for both solutions.


Joerg Received on Mon Sep 19 2011 - 05:57:44 CDT

Original text of this message