From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: performance problems with raid10,f2 Date: Tue, 25 Mar 2008 16:13:28 +1100 Message-ID: <18408.35320.92714.891870@notabene.brown> References: <20080314231151.GA14568@rap.rap.dk> <20080320172817.GA27070@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Sender: linux-raid-owner@vger.kernel.org To: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thursday March 20, keld@dkuug.dk wrote: > On Sat, Mar 15, 2008 at 12:11:51AM +0100, Keld J=F8rn Simonsen wrote: > > Hi > >=20 > > I have a 4 drive array with 1 TB Hitachi disks, formatted as raid10= ,f2 > >=20 > > I had some strange observations: > >=20 > > 1. while resyncing I could get the raid to give me about 320 MB/s i= n > > sequential read, which was good. After resync had been done, and wi= th > > all 4 drives active, I only get 115 MB/s. >=20 > This was reproducable. I dont know what could be wrong. Is this with, or without, your patch to avoid "read-balancing" for raid10/far layouts? It sounds like it is without that patch ???? NeilBrown > I tried to enlarge my readahed, but the system did not allow me to ha= ve=20 > more than a 2 MiB readahed, - well that should be ok for a 4 disk arr= ay > with 256 kiB chunks? >=20 > I did try to have chunks of 64 kiB - but no luck. >=20 > It seemed like it is something that the resync process builds up. > What could it be? >=20 > Best regards > keld > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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