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From: Markus Schaber <schabi@logix-tt.com>
To: PostgreSQL General <pgsql-general@postgresql.org>
Cc: Pgsql-Performance ((E-mail)) <pgsql-performance@postgresql.org>
Subject: Re: [PERFORM] Arguments Pro/Contra Software Raid
Date: Wed, 10 May 2006 15:54:43 +0200
Message-ID: <4461F0A3.60102@logix-tt.com> (raw)
In-Reply-To: <7779142C-B027-4C17-A67C-A7C220AADF80@slamb.org>
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>

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



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