Re: Huge Data sets, simple queries

От: Jeffrey W. Baker
Тема: Re: Huge Data sets, simple queries
Дата: ,
Msg-id: 1138568641.10923.6.camel@noodles
(см: обсуждение, исходный текст)
Ответ на: Re: Huge Data sets, simple queries  ("Luke Lonergan")
Список: pgsql-performance

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Huge Data sets, simple queries  ("Mike Biamonte", )
 Re: Huge Data sets, simple queries  ("Jeffrey W. Baker", )
 Re: Huge Data sets, simple queries  (Tom Lane, )
  Re: Huge Data sets, simple queries  ("Jeffrey W. Baker", )
   Re: Huge Data sets, simple queries  (Tom Lane, )
    Re: Huge Data sets, simple queries  (Tom Lane, )
 Re: Huge Data sets, simple queries  ("Luke Lonergan", )
  Re: Huge Data sets, simple queries  (hubert depesz lubaczewski, )
   Re: Huge Data sets, simple queries  (Michael Stone, )
  Re: Huge Data sets, simple queries  ("Jim C. Nasby", )
   Re: Huge Data sets, simple queries  ("Luke Lonergan", )
    Re: Huge Data sets, simple queries  (Kevin, )
    Re: Huge Data sets, simple queries  ("Jim C. Nasby", )
     Re: Huge Data sets, simple queries  ("Luke Lonergan", )
      Re: Huge Data sets, simple queries  ("Jim C. Nasby", )
       Re: Huge Data sets, simple queries  ("Luke Lonergan", )
        Re: Huge Data sets, simple queries  ("Jim C. Nasby", )
    Re: Huge Data sets, simple queries  ("Jeffrey W. Baker", )
     Re: Huge Data sets, simple queries  ("Luke Lonergan", )
      Re: Huge Data sets, simple queries  (PFC, )
       Re: Huge Data sets, simple queries  ("Luke Lonergan", )
      Re: Huge Data sets, simple queries  ("Steinar H. Gunderson", )
       Re: Huge Data sets, simple queries  ("Luke Lonergan", )
      Re: Huge Data sets, simple queries  ("Jeffrey W. Baker", )
       Re: Huge Data sets, simple queries  ("Luke Lonergan", )
        Re: Huge Data sets, simple queries  ("Jeffrey W. Baker", )
         Re: Huge Data sets, simple queries  (PFC, )
          Re: Huge Data sets, simple queries  ("Luke Lonergan", )
           Re: Huge Data sets, simple queries  ("Steinar H. Gunderson", )
           Re: Huge Data sets, simple queries  (Mike Rylander, )
         Re: Huge Data sets, simple queries  ("Luke Lonergan", )
       Re: Huge Data sets, simple queries  (Michael Stone, )
     Re: Huge Data sets, simple queries  (Alan Stange, )
 Re: Huge Data sets, simple queries  ("Luke Lonergan", )
  Re: Huge Data sets, simple queries  ("Jeffrey W. Baker", )
  Re: Huge Data sets, simple queries  (Charles Sprickman, )
   Re: Huge Data sets, simple queries  ("Luke Lonergan", )
  Re: Huge Data sets, simple queries  (hubert depesz lubaczewski, )
   Re: Huge Data sets, simple queries  ("Luke Lonergan", )
 Re: Huge Data sets, simple queries  (Michael Adler, )
 Re: Huge Data sets, simple queries  ("Craig A. James", )

On Sun, 2006-01-29 at 13:44 -0500, Luke Lonergan wrote:
> Depesz,
>
> > [mailto:] On Behalf Of
> > hubert depesz lubaczewski
> > Sent: Sunday, January 29, 2006 3:25 AM
> >
> > hmm .. do i understand correctly that you're suggesting that
> > using raid 10 and/or hardware raid adapter might hurt disc
> > subsystem performance? could you elaborate on the reasons,
> > please? it's not that i'm against the idea - i'm just curious
> > as this is very "against-common-sense". and i always found it
> > interesting when somebody states something that uncommon...

> Oh - and about RAID 10 - for large data work it's more often a waste of
> disk performance-wise compared to RAID 5 these days.  RAID5 will almost
> double the performance on a reasonable number of drives.

I think you might want to be more specific here.  I would agree with you
for data warehousing, decision support, data mining, and similar
read-mostly non-transactional loads.  For transactional loads RAID-5 is,
generally speaking, a disaster due to the read-before-write problem.

While we're on the topic, I just installed another one of those Areca
ARC-1130 controllers with 1GB cache.  It's ludicrously fast: 250MB/sec
burst writes, CPU-limited reads.  I can't recommend them highly enough.

-jwb

PS: Could you look into fixing your mailer?  Your messages sometimes
don't contain In-Reply-To headers, and therefore don't thread properly.



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