Re: 1 TB of memory - Mailing list pgsql-performance

From Michael Stone
Subject Re: 1 TB of memory
Date
Msg-id 20060317123121.GO15140@mathom.us
Whole thread Raw
In response to Re: 1 TB of memory  ("Luke Lonergan" <llonergan@greenplum.com>)
Responses Re: 1 TB of memory  ("Rodrigo Madera" <rodrigo.madera@gmail.com>)
List pgsql-performance
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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