Re: Capacity Planning

  • From: "LiShan Cheng" <exriscer@xxxxxxxxx>
  • To: "Jurijs Velikanovs" <j.velikanovs@xxxxxxxxx>
  • Date: Thu, 23 Feb 2006 14:13:27 +0100

Hi

They were custom applications. PL/SQL, Forms, Reports.

We migrated from Sun Solaris to HP-UX. The HP guy took Sun CPU clock speed
and turned that in HP-UX Itanium CPU clock speed. Mathematics basically. For
example

if Itanium CPU is twice as fast as a Sparc CPU, if the Sparc has a clock
speed of 400 Mhz and Itanium has 800 Mhz then 8 Sparc CPU is equivalent to

400 * 8 = 3200

3200 / 2 / 8 = 2

i.e 2 Itanium 800MHz CPU were equivalent to 8 400MHz Sparc CPU. I was amused
but hey he was the expert not me! :-)

I did tune a bit the application. I was not allowed to tune too much because
my job was migration and not tuning. Basically a Data Mart was killing the
server. There were 2 instances running in the server.

Cheers


--
LSC




On 2/23/06, Jurijs Velikanovs <j.velikanovs@xxxxxxxxx> wrote:
>
> > In my last project for example, a HP guy estimated 12 CPUs for a server
> > however in the practice we almost doubled otherwise the server would be
> CPU
> > bounded.
> What kind of application we are token about? Is it custom made?
> Have you tried to tune performance of the application before doubling
> resources?
> Was is RISC or Intel based server?
> Was it TOP SQL(-s) which consumed 90% of CPU?
>
> Jurijs
>
> On 2/23/06, LiShan Cheng <exriscer@xxxxxxxxx> wrote:
> > Hi
> >
> > Thanks for the reply.
> >
> > I am quite lost in this area basically becase I am quite reluctant about
> > capacity planning since I have seen quite a few and I have seen cero
> > success. Many times I would really like to ask the guy who did the plan
> how
> > he did it without knowing so many factors.
> >
> > In my last project for example, a HP guy estimated 12 CPUs for a server
> > however in the practice we almost doubled otherwise the server would be
> CPU
> > bounded.
> >
> > I understand it is necessary but... whose job should it be? DBA?
> Hardware
> > Vendor? Software Maker? System Admin? Mix of all is probably the answer
> but
> > then what information is needed by a DBA to perform such job?
> >
> > Shall I tkprof 10 sessions get the cpu time and multiply by the real
> number
> > of users I will have? :-)
> >
> > Cheers
> >
> > --
> > LSC
> >
> >
> >
> >
> > On 2/23/06, Jurijs Velikanovs <j.velikanovs@xxxxxxxxx> wrote:
> > > I'm interested in that question as well. I believe almost all DBA-s
> > > had, have, will have to answer it.
> > > The most difficult for me was CPU power, I/O throughput and Memory
> > > planning for home made (custom development) applications
> > > .
> > > By my experience you can spend tremendous amount of time (not just
> > > yours time) creating capacity plan for a particular system during an
> > > application development time. Work with analysts, designers,
> > > developers documenting detailed calculations and all assumptions. But
> > > end of the day you will get, a +/- 50% accurate result ;).
> > > If at the end the applications will not perform well enough the
> > > Developers will blame HW and will some think like "You need double HW
> > > resources to get XX sec response time". DBA-s and Admins would say "We
> > > already have some thing like top HW". It is always difficult to say if
> > > developers have done their work well without knowing the applications
> > > business.
> > > .
> > > At the moment I think that most effective way to plan that type of
> > > capacity is make assumptions based on you or others project members'
> > > previous experience.
> > > - If in the past you have worked with kind of systems you currently
> > > developing you know already the most important parts of application
> > > you have to pay attentions. This is there you have to concentrate your
> > > attention. In most cases it is something like 2% of overall
> > > application code. Describe, prototype, play with that bit and of the
> > > day you will get -/+ 10% accurate planning.
> > > - If in the past you have worked with much bigger systems, with huge
> > > amount of data processing you can think like. This system is 5 times
> > > smaller the system I have worked with. Presumably this system will run
> > > successfully on 2-3 times smaller HW and we will spend 2 times less
> > > time to tune it.
> > > - If you have chance to get information about system like you are
> > > going to implement (like OEBS, SAP, or other pre developed
> > > application, or the same functional application, or old system you
> > > going to replace), you can base your assumption on that information.
> > > .
> > > Later on then Developers will say you haven't enough HW capacity, you
> > > would be able to base you conclusion on a comparison of the developed
> > > application and other systems.
> > > .
> > > I don't think this approach is ideal, but at the moment I haven't
> found
> > better.
> > > I would be glad to hear others opinion.
> > >
> > > Thank you in advance,
> > > Jurijs
> > >
> > >
> > > On 2/23/06, LiShan Cheng < exriscer@xxxxxxxxx> wrote:
> > > > Hi
> > > >
> > > > I was wondering if anyone know any source about effective Oracle
> RDBMS
> > > > Capacity Planning. I mean effective because in the past I have seen
> many
> > so
> > > > called "Capacity Plan" which failed miserably in the practice. I am
> not
> > sure
> > > > how can a DBA perform Capacity Planning without knowing much about
> the
> > > > application?
> > > >
> > > > Cheers
> > > >
> > > >
> > > > LSC
> > > >
> > > >
> > >
> > >
> > > --
> > > Jurijs
> > > +44 7738 013090 (GMT)
> > > ============================================
> > > http://otn.oracle.com/ocm/jvelikanovs.html
> > >
> >
> >
>
>
> --
> Jurijs
> +44 7738 013090 (GMT)
> ============================================
> http://otn.oracle.com/ocm/jvelikanovs.html
>

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