From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcin Wanat Subject: Raid10 to Raid0 conversion Date: Sat, 22 Mar 2014 12:07:50 +0100 Message-ID: <532D6F06.1010901@forall.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; 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 Hi, i have 4disc RAID10 on my server and i am trying to grow it to 6 devices. As direct grow of RAID10 is unavailable so I decided to do it this way: RAID10->RAID0->Grow RAID0 to 3 devices->RAID0(3 devices)->RAID10(6devices) But i have problem on the first step. I have degraded my RAID10 array: # mdadm --detail /dev/md1 /dev/md1: Version : 1.1 Creation Time : Mon Sep 2 12:09:53 2013 Raid Level : raid10 Array Size : 1023996928 (976.56 GiB 1048.57 GB) Used Dev Size : 511998464 (488.28 GiB 524.29 GB) Raid Devices : 4 Total Devices : 2 Persistence : Superblock is persistent Update Time : Sat Mar 22 13:00:25 2014 State : clean, degraded Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Layout : near=2 Chunk Size : 512K Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 17 1 active sync /dev/sdb1 2 0 0 2 removed 4 8 49 3 active sync /dev/sdd1 And want to change it to RAID0: # mdadm /dev/md1 --grow --level=0 or: # mdadm /dev/md1 --grow --raid-devices=2 --level=0 but the result is always the same: mdadm: /dev/md1: could not set level to raid0 dmesg shows: md/raid0:md1: All mirrors must be already degraded! md: md1: raid0 would not accept array But the array is already degraded... What am I doing wrong ? I am using Centos 6.5 default version of kernel and mdadm. PS: I know that it is possible to grow RAID10 by creating new array with 3 drives and 3 missing and then move data between them, but i am trying to grow live system without any offline time. Regards, Marcin Wanat