X-Original-To: pgsql-general-postgresql.org@localhost.postgresql.org
Received: from localhost (mx1.hub.org [200.46.208.251])
	by postgresql.org (Postfix) with ESMTP id 4DC959FA3A6;
	Wed, 10 May 2006 10:54:46 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
	by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024)
	with ESMTP id 01097-05; Wed, 10 May 2006 10:54:32 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-
X-Greylist: from auto-whitelisted by SQLgrey-
Received: from mail.logix-tt.com (unknown [212.211.145.186])
	by postgresql.org (Postfix) with ESMTP id AC5479FA2FA;
	Wed, 10 May 2006 10:54:32 -0300 (ADT)
Received: from kingfisher.intern.logix-tt.com (p549D13DA.dip0.t-ipconnect.de
	[84.157.19.218])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by mail.logix-tt.com (Postfix) with ESMTP id 484CB65837;
	Wed, 10 May 2006 15:55:43 +0200 (CEST)
Received: from [127.0.0.1] (localhost [127.0.0.1])
	by kingfisher.intern.logix-tt.com (Postfix) with ESMTP id 1050518222EEA;
	Wed, 10 May 2006 15:54:44 +0200 (CEST)
Message-ID: <4461F0A3.60102@logix-tt.com>
Date: Wed, 10 May 2006 15:54:43 +0200
From: Markus Schaber <schabi@logix-tt.com>
Organization: Logical Tracking and Tracing International AG, Switzerland
User-Agent: Debian Thunderbird 1.0.7 (X11/20051017)
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: PostgreSQL General <pgsql-general@postgresql.org>
Cc: "Pgsql-Performance ((E-mail))" <pgsql-performance@postgresql.org>
Subject: Re: [PERFORM] Arguments Pro/Contra Software Raid
References: <e3pmkc$12mk$1@news.hub.org>
	<473FC220-A52C-4954-81E9-A14ED33164C2@blighty.com>
	<4460BA8B.7010600@commandprompt.com>
	<4F853BBA-175C-4B3E-BAF4-AA34B80DF6EF@blighty.com>
	<4460DED4.2090103@commandprompt.com>
	<7779142C-B027-4C17-A67C-A7C220AADF80@slamb.org>
In-Reply-To: <7779142C-B027-4C17-A67C-A7C220AADF80@slamb.org>
X-Enigmail-Version: 0.93.0.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Archive-Number: 200605/428
X-Sequence-Number: 95220

Hi, Scott & all,

Scott Lamb wrote:

> I don't know the answer to this question, but have you seen this tool?
> 
>     http://brad.livejournal.com/2116715.html

We had a simpler tool inhouse, which wrote a file byte-for-byte, and
called fsync() after every byte.

If the number of fsyncs/min is higher than your rotations per minute
value of your disks, they must be lying.

It does not find as much liers as the script above, but it is less
intrusive (can be ran on every low-io machine without crashing it), and
it found some liers in-house (some notebook disks, one external
USB/FireWire to IDE case, and an older linux cryptoloop implementations,
IIRC).

If you're interested, I can dig for the C source...

HTH,
Markus




-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf.     | Software Development GIS

Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org