From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: raid10 far layout outperforms offset at writing? (was: Help with chunksize on raid10 -p o3 array) Date: Wed, 17 Dec 2008 15:34:43 +0100 Message-ID: <20081217143443.GA6467@rap.rap.dk> References: <20081217124154.GA5406@rap.rap.dk> <4948F590.2050007@rabbit.us> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <4948F590.2050007@rabbit.us> Sender: linux-raid-owner@vger.kernel.org To: Peter Rabbitson Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Wed, Dec 17, 2008 at 01:50:24PM +0100, Peter Rabbitson wrote: > Keld J=F8rn Simonsen wrote: > > I found this old message: > >=20 > >> Peter Rabbitson > >> Mon, 19 Mar 2007 06:14:38 -0800 > >> > >=20 > > The links were not valid anymore. I wanted to see the results and=20 > > possibly include the results in the performance wiki page > > I would appreciate some new links here. >=20 > I apologize, I don't have the data available anymore. ' OK. > > Furthermore some comments to the post: My take on o3 vs f3 is that = both > > in theory and practice f3 should be much faster for sequential read= ing, > > as the layout is equivalent to raid0. For random reading and sequen= tial > > and random writing f3 and o3 (and the same goes for the more normal= f2 > > vs o2) should be about the same, especially when a filesystem and > > its associated elevator algorithm is employed. >=20 > Yes, this is what I also concluded since I wrote this email. I am in = the > process of upgrading my raid setup, and while I am at it I am leaving > 5GB blank partitions at the start of all my workstations spindles, so= I > can get some real testing at night. I will share my methodology with = the > list before I commence testing (which should take about 20 days the w= ay > I am planing it). I have tried to persuade Neil to change the description for MD to reflect the above, but until now with no luck. I look forward to see your new tests! > But first comes the vacation - happy holidays to you too guys. Yes, happy holidays to all! Best regards Keld -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html