From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: performance problems with raid10,f2 Date: Thu, 20 Mar 2008 18:28:17 +0100 Message-ID: <20080320172817.GA27070@rap.rap.dk> References: <20080314231151.GA14568@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: <20080314231151.GA14568@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids 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,f= 2 >=20 > I had some strange observations: >=20 > 1. while resyncing I could get the raid to give me about 320 MB/s in > sequential read, which was good. After resync had been done, and with > all 4 drives active, I only get 115 MB/s. This was reproducable. I dont know what could be wrong. I tried to enlarge my readahed, but the system did not allow me to have= =20 more than a 2 MiB readahed, - well that should be ok for a 4 disk array with 256 kiB chunks? I did try to have chunks of 64 kiB - but no luck. It seemed like it is something that the resync process builds up. What could it be? 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