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From: Willy Tarreau <w@1wt.eu>
To: Tim Schmielau <tim@physik3.uni-rostock.de>
Cc: "Ismail Dönmez" <ismail@pardus.org.tr>, linux-kernel@vger.kernel.org
Subject: Re: Abysmal disk performance, how to debug?
Date: Sat, 20 Jan 2007 21:31:41 +0100	[thread overview]
Message-ID: <20070120203140.GE25307@1wt.eu> (raw)
In-Reply-To: <Pine.LNX.4.63.0701202124180.23674@gockel.physik3.uni-rostock.de>

On Sat, Jan 20, 2007 at 09:28:57PM +0100, Tim Schmielau wrote:
> On Sat, 20 Jan 2007, Willy Tarreau wrote:
> 
> > Anyway, in your situation with a very small buffer, this should not 
> > change by more than half a second or so.
> 
> Well, his buffer is not small. He has half a GB of RAM, so when 
> writing 1 GB the buffer would roughly double the dd speed, exactly as he 
> has shown us.

yes, but he sees the opposite : when using half of the memory for the
buffer, he has low speed. When shorting cache size to 2% only, he doubles
his speed.

> Anyways, instead of always just posting similar answers to yours, I'll 
> have dinner now. :-)

:-)
Willy


  reply	other threads:[~2007-01-20 20:32 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-20 17:20 Abysmal disk performance, how to debug? Ismail Dönmez
2007-01-20 17:45 ` Willy Tarreau
2007-01-20 17:52   ` Ismail Dönmez
2007-01-20 18:03     ` Willy Tarreau
2007-01-20 18:06       ` Ismail Dönmez
2007-01-20 19:44       ` Sunil Naidu
2007-01-20 19:56         ` Stephen Clark
2007-01-20 20:09           ` Willy Tarreau
2007-01-21  3:41             ` Stephen Clark
2007-01-21  4:06               ` Gene Heskett
2007-01-27 19:43             ` Bill Davidsen
2007-02-03 17:22               ` Elladan
2007-01-20 20:05         ` Willy Tarreau
2007-01-20 20:11           ` Ismail Dönmez
2007-01-20 20:10     ` Tim Schmielau
2007-01-20 20:16       ` Ismail Dönmez
2007-01-20 20:19         ` Willy Tarreau
2007-01-20 20:28           ` Tim Schmielau
2007-01-20 20:31             ` Willy Tarreau [this message]
2007-01-20 20:21         ` Tim Schmielau
2007-01-20 20:28       ` Willy Tarreau
2007-01-20 20:39         ` Tim Schmielau
2007-01-20 21:24           ` Willy Tarreau
2007-01-20 21:41             ` Tim Schmielau
2007-01-20 21:12       ` Sunil Naidu
2007-01-20 22:00         ` Tim Schmielau
2007-01-20 23:47           ` Sunil Naidu

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