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Home -> Community -> Mailing Lists -> Oracle-L -> Re: FW: Disk capacity planning
Mladen,
I agree you can measure how many IOs are being done and how many a disk subsystem, such as those provided by EMC, can perform and still give "good" performance. What I meant is that it is hard and some would say impossible to estimate how many IOs per sec a new application will do. A combination of paper calculations, testing, experience and looking at comparable systems will help to provide a good estimate.
Cheers,
Chris
Quoting Mladen Gogala <mgogala_at_adelphia.net>:
> Oh, but it is done, you only need to ask. EMC routinely measures how many
> I/Os
> per second can they perform and they even have tools to measure it. Speaking
> of
> monitoring I/O, there used to be an old OS, which is mostly dead today and it
> used
> to have command monitor io/item=queue which would show length of the I/O
> queues
> per device, which was extremely useful, because you could quickly find out
> which
> devices are "hot" and which are not.
>
>
> On 2004.01.20 04:19, chris_at_thedunscombes.f2s.com wrote:
> > Cary,
> >
> > Good answer. The problem is most people concentrate on bytes because it's
> > relatively easy and everyone understands it. IOs per sec is much harder to
>
> > calculate for a new system and hence it's not normally done.
> >
> > Cheers,
> >
> > Chris Dunscombe
> >
> >
> >
> > Quoting Cary Millsap <cary.millsap_at_hotsos.com>:
> >
> > > I don't think this one made it through on my first attempt.
> > >
> > >
> > >
> > > Cary Millsap
> > > Hotsos Enterprises, Ltd.
> > > http://www.hotsos.com
> > > Nullius in verba
> > >
> > > Upcoming events:
> > > - Performance <http://www.hotsos.com/training/PD101.html> Diagnosis
> > > 101: 1/27 Atlanta
> > > - SQL Optimization 101: 2/16 Dallas
> > > - Hotsos Symposium 2004 <http://www.hotsos.com/events/symposium/2004> :
> > > March 7-10 Dallas
> > > - Visit www.hotsos.com for schedule details...
> > >
> > > -----Original Message-----
> > > Sent: Tuesday, January 13, 2004 5:54 PM
> > > To: 'ORACLE-L_at_fatcity.com'
> > >
> > >
> > >
> > > Counting bytes is far, far, FAR less important than counting
> > > I/O-per-second (IOps) requirements and making sure that you have enough
> > > total capacity to handle your system's peak I/O loads. Counting bytes is
> > > important too, but what many people find is that the byte-counting
> > > exercise will result in the sub-verdict of needing far fewer disk drives
> > > than you'll really, truly need.
> > >
> > >
> > >
> > > The way I'd recommend structuring your project is to evaluate the
> > > following:
> > >
> > >
> > >
> > > - How many bytes will you need to store your data? How many
> > > disks is that? Call the answer B.
> > >
> > > - How many disks will you need to meet your IOps requirements?
> > > Call the answer P.
> > >
> > > - How many disks will you need to meet your availability
> > > requirements? Call the answer A.
> > >
> > > - (Consider other attributes as necessary, like perhaps I/O
> > > throughput requirements.)
> > >
> > >
> > >
> > > Roughly speaking, the number of disks you'll need to buy is max(B, P, A,
> > > .). It's more complicated than that because you'll need to segment your
> > > total drive set into sensibly-sized arrays, you'll be able to buy some
> > > disks now then some later, and so on, but this is the general gist. The
> > > important thing is to have enough hardware to meet *all* of the
> > > constraints your business will place upon your system.
> > >
> > >
> > >
> > > Cary Millsap
> > > Hotsos Enterprises, Ltd.
> > > http://www.hotsos.com
> > > Nullius in verba
> > >
> > > Upcoming events:
> > > - Performance <http://www.hotsos.com/training/PD101.html> Diagnosis
> > > 101: 1/27 Atlanta
> > > - SQL Optimization 101: 2/16 Dallas
> > > - Hotsos Symposium 2004 <http://www.hotsos.com/events/symposium/2004> :
> > > March 7-10 Dallas
> > > - Visit www.hotsos.com for schedule details...
> > >
> > > -----Original Message-----
> > > Rhojel_Echano_at_sgs.com
> > > Sent: Tuesday, January 13, 2004 12:29 AM
> > > To: Multiple recipients of list ORACLE-L
> > >
> > >
> > >
> > >
> > > Hi everyone!
> > >
> > > Can anybody point me to any good documentation regarding disk capacity
> > > planning? Sharing your experience or approach will also give me so much
> > > help. I'd like to know other people's approach on forecasting the growth
> > > of their databases particularly on determining the (growth) rate of disk
> > > space usage and on deciding when to add and how many disk to add on an
> > > Oracle server.
> > >
> > > Thanks in advance.
> > >
> > > Best Regards,
> > > Rhojel
> > >
> > >
> >
> >
> > Chris Dunscombe
> >
> > chris_at_thedunscombes.f2s.com
> >
> > -------------------------------------------------
> > Everyone should have http://www.freedom2surf.net/
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author:
> > INET: chris_at_thedunscombes.f2s.com
> >
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>
> --
> Mladen Gogala
> Oracle DBA
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Mladen Gogala
> INET: mgogala_at_adelphia.net
>
> Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> San Diego, California -- Mailing list and web hosting services
> ---------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
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>
Chris Dunscombe
chris_at_thedunscombes.f2s.com
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: chris_at_thedunscombes.f2s.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Wed Jan 21 2004 - 03:34:25 CST
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