Re: 1 TB of memory

From: Michael Stone
Subject: Re: 1 TB of memory
Date: ,
Msg-id: 20060317123121.GO15140@mathom.us
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In response to: Re: 1 TB of memory  ("Luke Lonergan")
Responses: Re: 1 TB of memory  ("Rodrigo Madera")
List: pgsql-performance

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1 TB of memory  (Jim Nasby, )
 Re: 1 TB of memory  ("Joshua D. Drake", )
 Re: 1 TB of memory  (Ron Peacetree, )
 Re: 1 TB of memory  ("Matthew Nuzum", )
 Re: 1 TB of memory  ("Luke Lonergan", )
  Re: 1 TB of memory  ("Luke Lonergan", )
  Re: 1 TB of memory  (Josh Berkus, )
   Re: 1 TB of memory  ("Luke Lonergan", )
  Re: 1 TB of memory  (Michael Stone, )
   Re: 1 TB of memory  ("Rodrigo Madera", )
  Re: 1 TB of memory  ("Jim C. Nasby", )
   Re: 1 TB of memory  ("Luke Lonergan", )
    Re: 1 TB of memory  ("Merlin Moncure", )
     Re: 1 TB of memory  (Scott Marlowe, )
      Re: 1 TB of memory  (Vivek Khera, )
 Re: 1 TB of memory  (Alex Stapleton, )
 Re: 1 TB of memory  ("Merlin Moncure", )
  Re: 1 TB of memory  (Vivek Khera, )
   Re: 1 TB of memory  ("Merlin Moncure", )
    Re: 1 TB of memory  (Vivek Khera, )
 Re: 1 TB of memory  ("Merlin Moncure", )

On Thu, Mar 16, 2006 at 10:44:25PM -0800, Luke Lonergan wrote:
>You'd be better off with 4 x $10K servers that do 800MB/s from disk each and
>a Bizgres MPP - then you'd do 3.2GB/s (faster than the SSD) at a price 1/10
>of the SSD, and you'd have 24TB of RAID5 disk under you.

Except, of course, that your solution doesn't have a seek time of zero.
That approach is great for applications that are limited by their
sequential scan speed, not so good for applications with random access.
At 3.2 GB/s it would still take over 5 minutes to seqscan a TB, so you'd
probably want some indices--and you're not going to be getting 800MB/s
per system doing random index scans from rotating disk (but you might
with SSD). Try not to beat your product drum quite so loud...

Mike Stone


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From: Evgeny Gridasov
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Subject: Re: Background writer configuration
From: "Luke Lonergan"
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Subject: Re: 1 TB of memory