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Re: Real World Experience of Oracle RAC and its ability to Scale

From: Walter Dorninger <walter.dorninger_at_aon.at>
Date: Wed, 20 Apr 2005 12:12:16 +0200
Message-ID: <pan.2005.04.20.10.12.05.66556@aon.at>


Here a short general rule of thumb for RAC:

(1) If you need PERFORMANCE - scale vertically (put more cpu's, memory, etc.) in your database machine.

(2) If you need HIGHAVAILABILITY scale horizontal means - use a cluster.

It is true that if you add cluster nodes instead of scaling vertically - you will gain some more performance BUT - not as much as scaling vertically - and at a higher cost (hardware + more administration)

Walter Dorninger

On Tue, 19 Apr 2005 13:39:45 +0100, Ian Turner wrote:

> Hi,
>
> I'm currently involved in a evaluation of an application that uses of Oracle
> RAC to scale horizontally.
>
> At full production volumes the supplier is recommending a 12-node database
> cluster - using 2CPU commodity servers. Although the transaction rates are
> likely to be low, probably only:
> - 1 update transaction (consisting of perhaps 10 updates/inserts) per
> second.
> - 10 queries/sec
> on average during the day with more queries and less updates overnight .
> Peak volumes are unlikely to be significantly higher.
>
> In the application architecture of the product some application components
> are hosted on the database server. This provides a standard building block
> to scale the application - so the vendor says.
>
> Normally I would expect to separate the application tier from the database
> tier, and believe that a single database server (4CPU's perhaps) would
> easily be able to handle this kind of transaction load. But with this
> shared server the vendor recommends scaling is by adding these combined
> application/database server's into the cluster.
>
> My understanding is that Oracle RAC would typically be deployed with < 5
> nodes. So I'm looking to identify any real world examples of RAC clusters
> and the transaction rates/numbers of nodes.
>
> I would also be interested to know if there are:
> - any recommendations as to the maximum number of nodes in a RAC cluster
> - any RAC design principles that we should ensure the vendor has followed
> - areas we could/should monitor when performing an assessment of the
> application.
> - ways of predicting RAC performance as additional nodes are added (we are
> unlikely to be able to test the application with 12 nodes so will have to
> factor this up from fewer nodes).
>
> Any other comments on the general stability of the Oracle RAC platform in
> real world production environments would also be appreciated.
>
> regards
>
> Ian
Received on Wed Apr 20 2005 - 05:12:16 CDT

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