From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: raind-1 resync speed slow down to 50% by the time it finishes Date: Fri, 31 Jul 2009 20:10:41 +0200 Message-ID: <20090731181041.GA11756@rap.rap.dk> References: <20090730073554.GA17665@cthulhu.home.robinhill.me.uk> <20090730101846.GA17332@rap.rap.dk> <72dbd3150907301311t5abef2fai91cdae154b987d33@mail.gmail.com> <20090731175455.GA11463@rap.rap.dk> 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: <20090731175455.GA11463@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: David Rees Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, Jul 31, 2009 at 07:54:55PM +0200, Keld J=F8rn Simonsen wrote: > On Thu, Jul 30, 2009 at 01:11:20PM -0700, David Rees wrote: > > 2009/7/30 Keld J=F8rn Simonsen : > > > I think raid10,f2 only degrades 10-20 % while raid1 can degrade a= s much > > > as 50 %. For writing it is about the same, given that you use a f= ile > > > system on top of the raid. > >=20 >=20 > > Random/small reads far: Up to 100% faster >=20 > Actually a bit more, due to that far only uses the fastest half of th= e > disks. One test shows 132 % faster, which is consistent with theory. >=20 > > Random/small reads near: Up to 100% faster >=20 > One test shows 156 % faster. I meant 56 % faster. So one test (done by myself) shows far to be 132 % faster than single disk, and near to be 56 % faster. Given the behaviour of near and far I believe the tests to be representative of the near/far performance for random reading. 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