From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wols Lists Subject: Re: Impossibly level change request for RAID1 Date: Wed, 15 Nov 2017 17:14:54 +0000 Message-ID: <5A0C760E.9010105@youngman.org.uk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Santiago DIEZ , Linux Raid LIST List-Id: linux-raid.ids On 15/11/17 16:52, Santiago DIEZ wrote: > Hi, > > I started by mistake a raid as RAID1 with 5 disks when my desire was > to start it as RAID5. Technically, there is no data at all so I could > entirely recreate the raid but this is NOT what I want. I'm taking > this opportunity as an exercise to change a raid level. > > The initial state of the raid is: > md9 : active raid1 sda9[0] sdb9[1] sdc9[2] sdd9[3] sde9[4] > 5846755328 blocks super 1.2 [5/5] [UUUUU] > bitmap: 0/44 pages [0KB], 65536KB chunk > > # I tried to change the level with: > mdadm /dev/md9 --grow --level=5 > # But got the error : > mdadm: Impossibly level change request for RAID1 I'll leave the rest for someone else (or maybe me later :-) but just to explain the "impossible level change", you cannot change a mirror with more than two active devices. You need to have two active, three spares, before it will change. Cheers, Wol