From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Tor_Arne_Vestb=F8?= Subject: Re: Creating RAID5 with four devices and end up with 5 (one removed and one spare). Why? Date: Mon, 3 Mar 2008 10:29:58 +0100 Message-ID: <47CBC516.5050904@gmail.com> References: <47CBBD11.4020501@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII"; format="flowed" Return-path: In-Reply-To: <20080303091952.GA1125@cthulhu.home.robinhill.me.uk> References: <20080303091952.GA1125@cthulhu.home.robinhill.me.uk> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Thanks for your reply Robin! Robin Hill wrote: >> So what i don't get is: >> >> 1. Why is mdadm --examine listing "3 3 0 0 3 >> faulty removed" and telling me I have a failed device? >> 2. Why is one of the actual disks (sdf) used as a spare, even though I >> didn't ask for it? >> >> Thanks for any tips or insights which may put me on the right track :) >> > This is perfectly normal (and explained in the manual page) - the RAID5 > array is created in an initially degraded state, then rebuilt. This > means the array can be available for use immediately, with the rebuild > taking place in the background. You'll need to run 'mdadm -w /dev/md0' > to force the array into read-write mode (it's currently started in > auto-read-only mode) and the resync will then begin. I had a suspicion this was the case for question number two -- why one of the disks initially are marked as spares. Good to have that cleared up! But does that explain why mdadm believes I have another disk, a fifth disk, that has been removed? The ID numbers of the real disks are 0,1,2,4 but I would expect 0,1,2,3: Number Major Minor RaidDevice State this 1 8 49 1 active sync /dev/sdd1 0 0 8 33 0 active sync /dev/sdc1 1 1 8 49 1 active sync /dev/sdd1 2 2 8 65 2 active sync /dev/sde1 3 3 0 0 3 faulty removed <-- What's up? 4 4 8 81 4 spare /dev/sdf1 Thanks! Tor Arne