From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-15?Q?Karsten_R=F6mke?= Subject: misunderstanding of spare and raid devices? Date: Thu, 30 Jun 2011 12:51:37 +0200 Message-ID: <4E0C5539.4030000@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello, I'm searching some hours / minutes to create a raid5 device with 4 disks and 1 spare: I tried first with the opensuse tool but no success as I want, so I tried mdadm Try: mdadm --create /dev/md0 --level=5 --raid-devices=4 --spare-devices=1 /dev/sda3 /dev/sdb2 /dev/sdc5 /dev/sdd5 /dev/sde5 leads to Personalities : [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] md0 : active (auto-read-only) raid5 sdd5[5](S) sde5[4](S) sdc5[2] sdb2[1] sda3[0] 13759296 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_] 2 spares - I don't understand that. kspace9:~ # mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sda3 /dev/sdb2 /dev/sdc5 /dev/sdd5 leads to md0 : active (auto-read-only) raid5 sdd5[4](S) sdc5[2] sdb2[1] sda3[0] 13759296 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_] 1 spare - but why - I expect 4 active disks and 1 spare kspace9:~ # mdadm --create /dev/md0 --level=5 --raid-devices=5 /dev/sda3 /dev/sdb2 /dev/sdc5 /dev/sdd5 /dev/sde5 leads to md0 : active (auto-read-only) raid5 sde5[5](S) sdd5[3] sdc5[2] sdb2[1] sda3[0] 18345728 blocks level 5, 64k chunk, algorithm 2 [5/4] [UUUU_] That's what I want, but I reached it more or less by random. Where is my "think-error" (in german). I use kspace9:~ # mdadm --version mdadm - v3.0.3 - 22nd October 2009 Any hints would be nice karsten