From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Benchmarks: Linux Kernel RAID vs a Hardware RAID setup Date: Mon, 21 Jul 2008 12:58:28 -0400 Message-ID: <4884C034.6020502@tmr.com> References: <1216130769.5633.318.camel@sam.localdomain> <20080715163932.GA23164@rap.rap.dk> <1216180685.5633.364.camel@sam.localdomain> <20080716044718.GA7626@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20080716044718.GA7626@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= Cc: Ben Martin , linux-raid@vger.kernel.org List-Id: linux-raid.ids Keld J=F8rn Simonsen wrote: > On Wed, Jul 16, 2008 at 01:58:05PM +1000, Ben Martin wrote: > =20 >> On Tue, 2008-07-15 at 18:39 +0200, Keld J=F8rn Simonsen wrote: >> =20 >>> On Wed, Jul 16, 2008 at 12:06:09AM +1000, Ben Martin wrote: >>> =20 >> One interesting question about the r10 layouts, if f2/o2 perform bet= ter >> than n2 why is the default for creation still n2? Just like mkfs.xfs >> determining the raid chunk and stripe size for you (assuming you don= 't >> use LVM to circumvent this, gah!), shouldn't mdadm select the "faste= st" >> --layout as the default for RAID-10? >> =20 > > Perhaps. I think Neil first implemented "near", and more or less at t= he same > time "far" - but to him the main thing was "near". This was 2.6.9. Th= en > in 2.6.18 he implemented "offset". In the early days the > characteristics of each layout were not well known. It is only in the > last year or so I have seen benchmarks with n2, f2 and o2. I admit that I have done "raw device performance" benchmarks with n2 an= d=20 f2, and neglected o2 completely, so I rely on other's work. However, I=20 am most often bitten by raid5 issues, so I have been paying most=20 attention to them. --=20 Bill Davidsen "Woe unto the statesman who makes war without a reason that will stil= l be valid when the war is over..." Otto von Bismark=20 -- 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