From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Spannbauer Subject: Re: Raid1: sdb has a lot mor work then sda Date: Tue, 24 Apr 2012 17:02:49 +0200 Message-ID: <4F96C099.6000506@marco.de> References: <4F96BCC9.9080003@marco.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello, here is a screendump of a atop -dD in such a situation. Regards Daniel Am 04/24/2012 05:00 PM, schrieb Roberto Spadim: > it=B4s a read, a write, or both operation? > about load i think it=B4s a very big read (sdb) with a very low write= (sda) > the disk balance on raid1 is based on nearest (current position - nex= t > read position) disk > on a sequencial read only one disk is better used >=20 > i checked that raid1 'have this problem' but it=B4s a hardware limit,= i > didn=B4t found a solution, maybe others friends can found >=20 > Em 24 de abril de 2012 11:46, Daniel Spannbauer > escreveu: >=20 > Hello, >=20 > at the moment I'm trying to find a bottleneck on my lamp-server w= ith > opensuse 11.4 (Kernel 2.6.37.6) >=20 > Sometimes the system has a very poor performance because of a hig= h > io-wait. > If I watch the systems disk-access with "atop -dD" I can see that= sda is > the most of the time at a load of 10%, sdb sometimes is at 100% o= r > higher at the same time. >=20 > In my opinion in a Raid1-System both disk should have nearly the > same load. >=20 > Or may I wrong whis this? >=20 > Both harddisks where changed 3 Weeks ago, /proc/mdstat shows that= the > rebuild was successfull and the array is functional. Today I've c= hanged > th SATA-Cable and the Port on the Maindboard of sdb, but the beha= viour > is still the same. Both disks passed the extended smart-self-test= =2E >=20 > Any ideas about that? >=20 > Regards >=20 > Daniel >=20 >=20 >=20 > -- > Daniel Spannbauer Software Entwicklung > marco Systemanalyse und Entwicklung GmbH Tel +49 8333 9233-27 > Fax -11 > Rechbergstr. 4 - 6, D 87727 Babenhausen Mobil +49 171 4033220 > > http://www.marco.de/ Email ds@marco.de > > Gesch=E4ftsf=FChrer Martin Reuter HRB 171775 Amtsgeri= cht M=FCnchen > -- > To unsubscribe from this list: send the line "unsubscribe linux-r= aid" in > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.htm= l >=20 >=20 >=20 >=20 > --=20 > Roberto Spadim > Spadim Technology / SPAEmpresarial --=20 Daniel Spannbauer Software Entwicklung marco Systemanalyse und Entwicklung GmbH Tel +49 8333 9233-27 Fax -1= 1 Rechbergstr. 4 - 6, D 87727 Babenhausen Mobil +49 171 4033220 http://www.marco.de/ Email ds@marco.de Gesch=E4ftsf=FChrer Martin Reuter HRB 171775 Amtsgericht M=FC= nchen -- 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