pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Yeb Havinga <yebhavinga@gmail.com>
To: pgsql-performance@postgresql.org
Subject: Re: Testing Sandforce SSD
Date: Wed, 28 Jul 2010 15:45:23 +0200
Message-ID: <4C503473.5080105@gmail.com> (raw)
In-Reply-To: <e7e05556-9a42-11df-9b6a-001cc0cda50c@msgid.mathom.us>
References: <4C4A9452.9070100@gmail.com>
	<4C4B1F84.5030306@2ndquadrant.com>
	<4C4C83DF.3010703@gmail.com>
	<4C4C8CCC.7080406@gmail.com>
	<alpine.DEB.2.00.1007261045470.20471@aragorn.flymine.org>
	<4C4D6396.5020707@gmail.com>
	<4C4DAAE8.3060501@2ndquadrant.com>
	<4C4DE50B.1060102@gmail.com>
	<4C4DE5C9.8090004@2ndquadrant.com>
	<AANLkTimwAqzvWvSfscqDKJDG3Yod=6KQ6e0Xo+c+k6s=@mail.gmail.com>
	<e7e05556-9a42-11df-9b6a-001cc0cda50c@msgid.mathom.us>

Michael Stone wrote:
> On Mon, Jul 26, 2010 at 03:23:20PM -0600, Greg Spiegelberg wrote:
>> I know I'm talking development now but is there a case for a pg_xlog 
>> block
>> device to remove the file system overhead and guaranteeing your data is
>> written sequentially every time?
>
> If you dedicate a partition to xlog, you already get that in practice 
> with no extra devlopment.
Due to the LBA remapping of the SSD, I'm not sure of putting files that 
are sequentially written in a different partition (together with e.g. 
tables) would make a difference: in the end the SSD will have a set new 
blocks in it's buffer and somehow arrange them into sets of 128KB of 
256KB writes for the flash chips. See also 
http://www.anandtech.com/show/2899/2

But I ran out of ideas to test, so I'm going to test it anyway.

regards,
Yeb Havinga




view thread (60+ messages)  latest in thread

Message-ID: <4C503473.5080105@gmail.com>
Permalink:  ../4C503473.5080105@gmail.com/
Also on:    postgresql.org/message-id/4C503473.5080105@gmail.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: yebhavinga@gmail.com
  Subject: Re: Testing Sandforce SSD
  In-Reply-To: <4C503473.5080105@gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox