От: Ron Johnson
Тема: Re: Tuning PostgreSQL
Дата: ,
Msg-id: 1059493575.7505.129.camel@haggis
(см: обсуждение, исходный текст)
Ответ на: Re: Tuning PostgreSQL  (Vivek Khera)
Ответы: Re: Tuning PostgreSQL  ("scott.marlowe")
Список: pgsql-performance

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Tuning PostgreSQL  ("Alexander Priem", )
 Re: Tuning PostgreSQL  ("Shridhar Daithankar", )
 Re: Tuning PostgreSQL  ("Shridhar Daithankar", )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
  Re: Tuning PostgreSQL  (Ang Chin Han, )
   Re: Tuning PostgreSQL  ("Shridhar Daithankar", )
    Re: Tuning PostgreSQL  (Ang Chin Han, )
     Re: Tuning PostgreSQL  ("Shridhar Daithankar", )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
   Re: Tuning PostgreSQL  ("Shridhar Daithankar", )
    Re: Tuning PostgreSQL  ("Alexander Priem", )
  Re: Tuning PostgreSQL  (Ron Johnson, )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
   Re: Tuning PostgreSQL  (Ron Johnson, )
   Re: Tuning PostgreSQL  (Andrew McMillan, )
    Re: Tuning PostgreSQL  ("Arjen van der Meijden", )
     Re: Tuning PostgreSQL  (Tom Lane, )
     Re: Tuning PostgreSQL  ("Balazs Wellisch", )
      Re: Tuning PostgreSQL  (Josh Berkus, )
 Re: Tuning PostgreSQL  ("Roman Fail", )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
   Re: Tuning PostgreSQL  (Josh Berkus, )
    Re: Tuning PostgreSQL  (Vincent van Leeuwen, )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
   Re: Tuning PostgreSQL  (Vincent van Leeuwen, )
    Re: Tuning PostgreSQL  (Bruno Wolff III, )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
   Re: Tuning PostgreSQL  (Andrew Sullivan, )
   Re: Tuning PostgreSQL  ("Jim C. Nasby", )
    Re: Tuning PostgreSQL  ("scott.marlowe", )
     Re: Tuning PostgreSQL  (Greg Stark, )
      Re: Tuning PostgreSQL  (Ron Johnson, )
     Re: Tuning PostgreSQL  (Vivek Khera, )
      Re: Tuning PostgreSQL  (Ron Johnson, )
       Re: Tuning PostgreSQL  ("scott.marlowe", )
        Re: Tuning PostgreSQL  (Ron Johnson, )
         Re: Tuning PostgreSQL  ("scott.marlowe", )
          Re: Tuning PostgreSQL  (Ron Johnson, )
           Re: Tuning PostgreSQL  ("scott.marlowe", )
            Re: Tuning PostgreSQL  (Ron Johnson, )
             Re: Tuning PostgreSQL, pt 2  (Ron Johnson, )
          Re: Tuning PostgreSQL  (Vivek Khera, )
      Re: Tuning PostgreSQL  (Will LaShell, )
  Re: Tuning PostgreSQL  ("Alexander Priem", )
   Re: Tuning PostgreSQL  (Ron Johnson, )
  Re: Tuning PostgreSQL  (Vivek Khera, )
 'View'-performance  ("Alexander Priem", )
  Re: 'View'-performance  (Tom Lane, )

On Tue, 2003-07-29 at 10:14, Vivek Khera wrote:
> >>>>> "GS" == Greg Stark <> writes:
>
> GS> "scott.marlowe" <> writes:
>
> GS> But you have to actually test your setup in practice to see if it
> GS> hurts. A big data warehousing system will be faster under RAID5
> GS> than under RAID1+0 because of the extra disks in the
> GS> stripeset. The more disks in the stripeset the more bandwidth you
> GS> get.
>
> Anyone have ideas on 14 spindles?  I just ordered a disk subsystem
> with 14 high speed (U320 15kRPM) SCSI disks to hook up with a dell
> PERC3/DC controller (only 128MB cache, though).

14 drives on one SCSI card, eh?  I'd be worried about saturating
the bus.

Maybe it's an old rule of thumb, but I would fill a SCSI chain
more than half full.

> My plan was to do RAID10, but I think I'll play with RAID5 again and
> see which gives me the best performance.  Unfortunatly, it is
> difficult to recreate the highly fragmented tables I have now (vacuum
> full takes over 14 hours on one of the tables) so I'm not sure how to
> best compare them.

Also IMO: if I needed something *really* high performance, I'd
start with a mobo that has dual PCI buses (133MB/s can get swamped
quickly by U320 devices) or PCI-X (but they're so new...).

Then:
- get dual U320 SCSI cards (one for each PCI bus)
- plug them into dual redundant fast path external storage controllers
  that have, oh, 512MB RAM cache *each*)
- dual port the drives, so they plug into both storage controllers

Since I wouldn't put 14 drives on one SCSI chain, double what I
just said, and only plug 7 drives in each controller.

If your app needs One Big Honkin' Device, use the Linux Volume
Manager (LVM) to merge the 2 RAID logical devices into one "super-
logical" device.

Yes, that's lot's of money, but is the data, and speed, important
enough?

--
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| Ron Johnson, Jr.        Home:              |
| Jefferson, LA  USA                                              |
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| "I'm not a vegetarian because I love animals, I'm a vegetarian  |
|  because I hate vegetables!"                                    |
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