From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin ESTRABAUD Subject: Re: restore 3disk raid5 after raidpartitions have been setup with xfs filesystem by accident Date: Wed, 21 Sep 2016 14:34:33 +0100 Message-ID: <57E28C69.1040500@mpstor.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Simon Becks , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 21/09/16 11:39, Simon Becks wrote: > Dear Developers & Gurus & Gods, > > i had a 3 disk software raid 5 (mdadm) on a buffalo terrastation. By > accident I reset the raid and the NAS put on a xfs filesystem on each > of the 3 partitions. > > sda6 sdb6 and sdc6 have been the raid5 member partitions. > > Now sda6 sdb6 and sdc6 only contain a xfs filesystem with some empty > default folder structure - my NAS created during the "reset". > This is clearly not ideal, but hopefully you can recreate the MD superblocks and re-assemble the RAID as it was before, but that will imply you knowing exactly what order the devices were in your array and what RAID level and chunksize you used. There are procedures online to attempt this somewhat safe (by telling MD to assemble read only) but really the first step in this case is usually to backup the raw partitions to files or new devices in case you mess up something during recovery. > Am I screwed or is there a chance to recreate the raid with the 3 > disks end up with the raid and the filesystem i had before? > Even if you manage to recreate the RAID superblocks and re-assemble as it used to be, part of the on RAID data will have been overwritten by the format of the individual partitions. Maybe enough that your filesystem will be corrupted beyond repair (at which point you can use utilities like the excellent "testdisk"). > any help is greatly appreciated. > Good luck! > Simon > Regards, Ben.