From mboxrd@z Thu Jan 1 00:00:00 1970 From: Harald Nikolisin Subject: Device utilization with RAID-1 Date: Tue, 16 Aug 2011 02:39:47 +0200 Message-ID: <4E49BC53.8040604@googlemail.com> Reply-To: hochglanz@googlemail.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Since a long time I'm unhappy with the performance of my RAID-1 system. Investigation with atop and iostat unveils that the disk utilization is always on a certain level although nothing happens on the system. In the case of reading or writing files the utilization boosts always to 100% for a long time. Very ugly examples are "Firefox starting" or "zypper updates". That is snapshot of the output of iostat: Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 7,33 0,00 43,33 5,91 0,33 43,18 33,32 24,43 sdb 0,00 0,00 0,00 7,33 0,00 43,33 5,91 0,35 45,59 39,73 29,13 md0 0,00 0,00 0,00 0,67 0,00 5,33 8,00 0,00 0,00 0,00 0,00 md1 0,00 0,00 0,00 0,33 0,00 5,33 16,00 0,00 0,00 0,00 0,00 md2 0,00 0,00 0,00 0,33 0,00 1,00 3,00 0,00 0,00 0,00 0,00 md3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 md4 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 md5 0,00 0,00 0,00 0,33 0,00 0,67 2,00 0,00 0,00 0,00 0,00 I checked with mdadm if a resync happens or so, but this is not the case. The state says "active" on all RAID devices - btw. what is the difference to "clean" ? thanks for any hints, harald