From mboxrd@z Thu Jan 1 00:00:00 1970 From: Emilio Hodge Subject: Problem creating raid10 f2 with 2 disks missing Date: Mon, 04 Mar 2013 20:59:25 +0100 Message-ID: <5134FD1D.8080908@home.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; 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 When creating a raid 10 near with 2 copies there are 4 possibilities. mdadm -C /dev/md/tmp -n4 -c512 -l10 -pn2 -amd missing /dev/sdb9 /dev/sdc9 missing mdadm -C /dev/md/tmp -n4 -c512 -l10 -pn2 -amd /dev/sda9 missing /dev/sdc9 missing mdadm -C /dev/md/tmp -n4 -c512 -l10 -pn2 -amd missing /dev/sdb9 missing /dev/sdd9 mdadm -C /dev/md/tmp -n4 -c512 -l10 -pn2 -amd /dev/sda9 missing missing /dev/sdd9 When creating a raid 10 far with 2 copies only 2 possibilities work, why? I discovered this when I failed disk 2 and 3 of a raid10 f2 and got a spectacular kernel oops. root@dimmel:~# mdadm -C /dev/md/tmp -n4 -c512 -l10 -pf2 -amd /dev/sda9 missing /dev/sdc9 missing mdadm: /dev/sda9 appears to be part of a raid array: level=raid10 devices=4 ctime=Mon Mar 4 18:14:29 2013 mdadm: /dev/sdc9 appears to be part of a raid array: level=raid10 devices=4 ctime=Sat Mar 2 23:28:12 2013 Continue creating array? y mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md/tmp started. root@dimmel:~# mdadm -C /dev/md/tmp -n4 -c512 -l10 -pf2 -amd missing /dev/sdb9 missing /dev/sdd9 mdadm: /dev/sdb9 appears to be part of a raid array: level=raid10 devices=4 ctime=Mon Mar 4 18:17:27 2013 mdadm: /dev/sdd9 appears to be part of a raid array: level=raid10 devices=4 ctime=Mon Mar 4 18:15:33 2013 Continue creating array? y mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md/tmp started. root@dimmel:~# mdadm -C /dev/md/tmp -n4 -c512 -l10 -pf2 -amd /dev/sda9 missing missing /dev/sdd9 mdadm: /dev/sda9 appears to be part of a raid array: level=raid10 devices=4 ctime=Mon Mar 4 18:15:02 2013 mdadm: /dev/sdd9 appears to be part of a raid array: level=raid10 devices=4 ctime=Sat Mar 2 23:28:12 2013 Continue creating array? y mdadm: Defaulting to version 1.2 metadata mdadm: RUN_ARRAY failed: Input/output error root@dimmel:~# mdadm -C /dev/md/tmp -n4 -c512 -l10 -pf2 -amd missing /dev/sdb9 /dev/sdc9 missing mdadm: /dev/sdb9 appears to be part of a raid array: level=raid10 devices=4 ctime=Mon Mar 4 18:14:29 2013 mdadm: /dev/sdc9 appears to be part of a raid array: level=raid10 devices=4 ctime=Mon Mar 4 18:15:02 2013 Continue creating array? y mdadm: Defaulting to version 1.2 metadata mdadm: RUN_ARRAY failed: Input/output error mdadm - v3.2.5 - 18th May 2012 Linux dimmel 3.7.1 #2 SMP Thu Dec 20 21:20:41 CST 2012 x86_64 AMD Phenom(tm) II X4 965 Processor AuthenticAMD GNU/Linux Emilio Hodge