From mboxrd@z Thu Jan 1 00:00:00 1970 From: Holger Mauermann Subject: LVM on raid10,f2 performance issues Date: Mon, 01 Dec 2008 01:00:32 +0100 Message-ID: <49332920.5010503@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids When I setup LVM on top of a 4 disk RAID 10 with f2 layout read/write performance is really worse - it's far below single drive speed... I did some testing with dd and hexdump and I noticed that after writing a 128k file (with 64k "X" and 64k "Y") to the lvol the data on the raw disks looks somewhat weird: sda: sdb: sdc: sdd: ---------------------- YYYY .... .... XXXX .... .... .... .... XXXX YYYY .... .... .... .... .... .... Any hints how to tune this? With LVM on a standard RAID 10 (n2) the data appears as expected on the disks: sda: sdb: sdc: sdd: ---------------------- YYYY YYYY XXXX XXXX .... .... .... .... .... .... .... .... .... .... .... ....