RE: Oracle RAC cost justification?

From: David <thump_at_cosmiccooler.org>
Date: Thu, 2 Jun 2005 18:38:18 -0700
Message-ID: <000c01c567dc$efdab100$6401a8c0@winston>

SMP machines don't scale in a linear fashion after a certain numbers of CPU's(Long ago I was told 14). That is why I was lead to believe MPP/RAC/OPS/RAC/Grid/Mesh was introduced.

With the right design it made and makes perfect sense.

Alas, Oracle has revamped it and marketed as in a way that makes execs = go,
wow cheap solution to big expensive SMP machines...well there are holes = in
that cheese.

It has it's place...just not many.
David

-----Original Message-----
From: oracle-l-bounce_at_freelists.org =
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of Niall Litchfield
Sent: Thursday, June 02, 2005 1:40 PM
To: tim_at_evdbt.com
Cc: oracle-l_at_freelists.org
Subject: Re: Oracle RAC cost justification?

Hi Tim
 On 6/2/05, Tim Gorman <tim_at_evdbt.com> wrote: =20
> Instead of arguing about whether RAC is good at scalability or HA or=20
> cost-effectiveness, how about citing specifics?

>=20

> Q1 - RAC and HA:

>=20

> - What does RAC do better than any other possible solution (i.e. OS=20
> clustering, DataGuard, volume replication, etc)? How and why?
> - What other solutions are better than RAC at HA and why?
 I'd argue that any solution that breaks the single location, single=20 database requirement of RAC will give better HA.=20  Q2 - RAC and scalability:

• When does RAC present a better scalability solution than, say, simply buying a larger server?
• What scalability bottlenecks does a RAC solution resolve better than alternatives (i.e. larger server, RAM disk, etc)?
• What other solutions are better than RAC at scalability and why?

Q3 - RAC and cost-effectiveness:

• Compare and contrast the explicit (and implicit) costs to a RAC versus non-RAC configuration for the following scenarios:
  • 8 CPUs of processing capacity required, no HA reqmts stated
  • 8 CPUs of processing capacity required, MTTR less than 1 hour
  • same as above for 64 CPUS of processing capacity I'd link those two. Implicit in your question seems to be the ideas = that=20
    1. you can satisfy your demand with a known number of CPUs and
    2. you already have that demand.=20 I see RAC as being a killer app for folk who *right now* need say 2 or = 4=20 cpus but may well need 8,16 or 32 as business takes off. If you go the=20 single instance route then what do you do, buy four times as much = hardware=20 as you currently need just in case? In addition for people who don't = know=20 what their cpu and memory requirements actually are RAC might well make=20 sense. (or they have platform limitations about how much hardware their = os=20 can sensibly address on a given node.) If i'm right the bundling of RAC = with

SE in 10g makes a huge amount of sense.=20  as for cost-effectiveness, as i was trying probably imperfectly to say, =

make sure you are comparing different solutions to the same business=20 problem.=20

--=20
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com

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Received on Thu Jun 02 2005 - 21:44:03 CDT