Re: Oracle RAC for scalability or High Availability only

On 2006-02-28, DA Morgan <damorgan_at_psoug.org> wrote:
> JEDIDIAH wrote:
>
>> OTOH, adding nodes to the cluster is not just about the cost of
>> the boxes or of Oracle. Each box is going to your network and storage
>> systems overhead.
>
> No more or less so than any other method of satisfying the same
> overhead. One can always choose to favour the networks by just limiting

        That overhead DOESN'T EXIST in a non-clustered solution.

        A single system != a collection of systems.

> the number of users but that is rarely a winning suggestion in a meeting
> with management.
>
>> That next box might require you to get another high
>> speed network switch (or 2 if you are being extra robust). The same goes
>> with your fiber switches. Then there's the question of whether or not
>> your storage array can handle that level of concurrency (nfs, iscsi or san).
>
> Again no more so than with any other box. 12 CPUs in one box versus
> 3x4CPU nodes does not add one iota of traffic to the public or storage
> networks.

        Except it's not the public networks (data or san) that are the problem. It's the brand new networks that have to be created in order to support a cluster. A large SMP machine doesn't require a dedicated high speed network to deal with with cache fusion.

>
> Yes it affects the memory interconnect used for cache fusion. But if
> that is your issue you have a very badly designed application.
>
>> It's not just 5x cheap liliputians against the big expensive
>> Gulliver.
>>
>> Then you've got the fun of your cluster fs and clusterware
>> interacting over those 5x boxes.
>
> And this is less than having two large boxes with DataGuard or Streams
> or Advanced Replication to attempt to achieve a high availability
> solution? Or do you just throw HA away?

        HA is really for people that actually need it and are willing to pay for it. RAC is no free lunch in this regard and shouldn't be portrayed as such. It involves it's own tradeoffs and cost escalations. Part of your solution will have to go up market from where it could have been otherwise.

>
>> RAC requires more interesting and more expensive storage
>> hardware then itself becomes an expensive single point of failure.
>
> I'll gladly debate that with you any time you wish. The cost of RAW
> devices versus cooked file systems is? The cost of OCFS2 is? The cost
> of a NetApp or EMC differs how? The cost of ASM is?

        Oracle by itself does not require a Netapp. What you can get bundled within a Dell 2850 will do.

        I think you are just accustomed to things like CX300's and Silkworms being strewn about for anyone that should happen to need one.

[deletia]

-- 

It is not true that Microsoft doesn't innovate. 

        They brought us the email virus.
                                                     
	In my Atari days, such a notion would have             |||
	been considered a complete absurdity.                 / | \

 Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
    ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
----------------------------------------------------------        
                http://www.usenet.com