From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Goryachev Subject: Re: Failed Raid 5 due to OS mbr written on one of the array drives Date: Wed, 4 Nov 2015 02:45:53 +1100 Message-ID: <5638D6B1.4010509@websitemanagers.com.au> References: <5637A92B.5010305@turmel.org> 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: Nicolas Tellier , Phil Turmel Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 04/11/15 01:21, Nicolas Tellier wrote: > Hi Phil, and thanks for taking the time to reply to me. > > I'm not sure I understood you advice correctly. > When you say leave off /dev/sdd, do you mean I should recreate a 3 > disks array like this : > mdadm --create --verbose --assume-clean /dev/md0 --level=5 > --metadata=1.2 --chunk=128 --data-offset=262144 --raid-devices=3 > /dev/sda1 /dev/sdb1 /dev/sdc1 No, but lucky you checked > Or a 4 disks array with no mention of /dev/sdd, like this (my instinct > tell me that wouldn't work) : > mdadm --create --verbose --assume-clean /dev/md0 --level=5 > --metadata=1.2 --chunk=128 --data-offset=262144 --raid-devices=4 > /dev/sda1 /dev/sdb1 /dev/sdc1 No, but lucky you checked > Or, as I was thinking originally, to put /dev/sdd as missing, like so : > mdadm --create --verbose --assume-clean /dev/md0 --level=5 > --metadata=1.2 --chunk=128 --data-offset=262144 --raid-devices=4 > /dev/sda1 /dev/sdb1 /dev/sdc1 missing /dev/sdd No, but lucky you checked What he means (I'm pretty sure) is that you should run the command: mdadm --create --verbose --assume-clean /dev/md0 --level=5 --metadata=1.2 --chunk=128 --data-offset=262144 --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 missing /dev/sdd but delete "/dev/sdd" from that, because you are using the wrong syntax. Specifically, run this command: mdadm --create --verbose --assume-clean /dev/md0 --level=5 --metadata=1.2 --chunk=128 --data-offset=262144 --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 missing The word missing replaces a device name, because the device doesn't exist. It doesn't say that the next device name is missing. > I'm tempted to subscribe to the mailing list, but I'm afraid of the > volume of e-mail I'm going to get. I originally tried to search > through the archives, but couldn't find anything relevant to my case. > I'm looking right now at the "timeout mismatch" results. The list isn't that busy, I would guess around 10 per day. You can always unsubscribe after you solve your problem, but staying subscribed will let you learn a lot about common issues, especially the drive timeout mismatch issues. Regards, Adam [SNIP] -- Adam Goryachev Website Managers www.websitemanagers.com.au