From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: Attempt to change raid1 to raid0 results in division error in kernel Date: Thu, 23 May 2013 20:40:13 -0500 Message-ID: <519EC4FD.1090800@hardwarefreak.com> References: <20130523104400.GA827@gbl-macbook> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130523104400.GA827@gbl-macbook> Sender: linux-raid-owner@vger.kernel.org To: Robert Goliasz Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 5/23/2013 5:44 AM, Robert Goliasz wrote: > Hi, > > When attempting to change raid level from 1 to 0 I don't even know if this is possible. > (I was doing some testing > trying to convert a raid1 array to a raid10 one), I got a division error. ... > gbl-macbook# mdadm --grow /dev/md0 -l 0 If it is possible, this command line won't work because you didn't specify a chunk size for the RAID0 stripe. Every striped array type requires a chunk size. > zsh: segmentation fault mdadm --grow /dev/md0 -l 0 > gbl-macbook# ... > Afterwards, my mounted filesystem (/dev/md0) disappeared (it's no longer > mounted), and all operations related to software raid seem to fail: Well of course. Experimenting with mdadm without knowing what you're doing will often result in lost/corrupted arrays and other forms of damage. At this point you should simply start a new thread and ask: "How do I convert a RAID1 array to RAID0?" or "How do I convert a RAID1 array to RAID10?" instead of working backwards from your mistakes here. -- Stan