Re: seqential vs random io - Mailing list pgsql-performance

From John A Meinel
Subject Re: seqential vs random io
Date
Msg-id 429257ED.6020004@arbash-meinel.com
Whole thread Raw
In response to seqential vs random io  ("David Parker" <dparker@tazznetworks.com>)
Responses Re: seqential vs random io  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
David Parker wrote:
> I just got a question from one our QA guys who is configuring a RAID 10
> disk that is destined to hold a postgresql database. The disk
> configuration procedure is asking him if he wants to optimize for
> sequential or random access. My first thought is that random is what we
> would want, but then I started wondering if it's not that simple, and my
> knowledge of stuff at the hardware level is, well, limited.....
>
> If it were your QA guy, what would you tell him?
>
> - DAP

Random. Sequential is always pretty fast, it is random that hurts.

The only time I would say sequential is if you were planning on
streaming large files (like iso images) with low load.

But for a DB, even a sequential scan will probably not be that much data.

At least, that's my 2c.

John
=:->

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