Re: Dual Processor Server or 2 x Single Processor RAC Nodes?

On Wed, 06 Apr 2005 11:52:06 +1000, Mike Cretan interested us by writing:

>
>
> My leaning at the moment is to go with OSE1 and use the existing SE as a
> backup server if things get really dire. Then if we outgrow the dual
> processor OSE1 box, or decide that we need higher availability, we can
> upgrade the OSE1 licence to standard edition and/or reactivate the support
> on the SE licence and go RAC then.
 

That's roughly what I was suggesting. And using RMAN, IMO life becomes pretty reasonable. Only recommendation: test those backups and practise the recovery procedure - frequently.

One significant glitch is the idea of 'reactivating support'. If you want to do that, it's traditionally been a retroactive subscription. But, as I said, often the economics work for the scenario to OSE1 & apply the savings to future activation.

Just make sure it's documented, as management WILL kick when it's time to add or upgrade licenses. Their memories tend to go like 'but you just had a vacation; but we just bought those licenses', never 'we saved so much and postponed our costs, so now we can afford to dp xyz and still be ahead'!

(And tell the rep I'm sorry as it's a lousy time of year for them & this kind of thing hurts.)

> One final question I have - is in regard to the performance overheads that
> RAC places on an installation. How would the performance of a two node
> blade server (single CPU's) running RAC compare with a single 2 x CPU box.
> Is RAC even designed to run on such a small installation?

That, my friend, is the whole purpose of RAC on SE. SE can only be used up to 4 CPUs, but the RAC allows any combination of machines to a total of 4 CPUs - 4CPU x 1 machine, 2x2, 1x4 are all legit. Economically, it allows you to have 4 very inexpensive 1 CPU machines instead of 1 expensive 4 CPU machine - that 'like totally' offsets the cost of SE.

I can't [legally] discuss performance, but Oracle's public numbers around RAC indicate nominal overhead going to RAC and near linear benefit with additional machines. I am not going to argue too much with those numbers other than to say, some development styles meet the criteria better than others. Ask their Sales Consultants for the specifics (they need/want something to do occasionally <g>).

-- 
Hans Forbrich                           
Canada-wide Oracle training and consulting
mailto: Fuzzy.GreyBeard_at_gmail.com   
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