From mboxrd@z Thu Jan 1 00:00:00 1970 From: LM Subject: Re: Level change from 4 disk RAID5 to 4 disk RAID6 Date: Tue, 11 Apr 2017 23:28:39 +0200 Message-ID: <20170411212839.GD25873@lars-laptop> References: <20170408214239.GF10267@lars-laptop> <58EB1AF4.5010005@youngman.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <58EB1AF4.5010005@youngman.org.uk> Sender: linux-raid-owner@vger.kernel.org To: Wols Lists , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, Apr 10, 2017 at 06:41:08AM +0100, Wols Lists wrote: >On 08/04/17 22:42, LM wrote: >> Hi, >> >> I have a 4 disk RAID5, the used dev size is 640.05 GB. Now I want to >> replace the 4 disks by 4 disks with a size of 2TB each. >> >> As far as I understand the man page, this can be achieved by replacing >> the devices one after another and for each device rebuild the degraded >> array with: >> >> mdadm /dev/md0 --add /dev/sdX1 > >Do you have a spare SATA port or whatever your drives are. If so, then >use the --replace option to mdadm, don't fail then add. You're risking a >drive failure taking out your array - not a good move. > >And if you don't have a spare port, $20 for a PCI card or whatever is a >good investment to keep your data safe. > >Have a look at the raid wiki - it tries to be a bit more verbose and >easily comprehensible than the man page. > >Cheers, >Wol Thx for hinting me at --replace, I missed it. Yes, I have a spare SATA port. I successfully tested it using loop devices: mdadm /dev/md/test --add-spare /dev/loop20 --replace /dev/loop10 --with /dev/loop20 mdadm /dev/md/test --add-spare /dev/loop21 --replace /dev/loop11 --with /dev/loop21 mdadm /dev/md/test --add-spare /dev/loop22 --replace /dev/loop12 --with /dev/loop22 mdadm /dev/md/test --add-spare /dev/loop23 --replace /dev/loop13 --with /dev/loop23 mdadm /dev/md/test --remove /dev/loop10 /dev/loop11 /dev/loop12 /dev/loop13 mdadm --grow /dev/md/test --size max mdadm --grow /dev/md/test --level=6 --raid-disk=4 --backup-file=/root/backup-md-test --force mdadm --grow /dev/md/test --array-size 407552 mdadm --grow /dev/md/test --raid-disk=4 --layout=normalise --backup-file=/root/backup-md-test