From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Turmel Subject: Re: Accidentally resized array to 9 Date: Sat, 30 Sep 2017 12:21:20 -0400 Message-ID: References: <0e59cefd-662f-bf77-0c32-49424d504c77@benshoshan.com> <20170929175524.57fea3b5@natsu> <20170930005005.68beae8b@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170930005005.68beae8b@natsu> Content-Language: en-GB Sender: linux-raid-owner@vger.kernel.org To: Roman Mamedov , Eli Ben-Shoshan Cc: linux-raid@vger.kernel.org, John Stoffel List-Id: linux-raid.ids On 09/29/2017 03:50 PM, Roman Mamedov wrote: > On Fri, 29 Sep 2017 10:53:57 -0400 > Eli Ben-Shoshan wrote: > >> I am just hoping that there might be a way that I can get the >> data back. > > In theory what you did was cut the array size to only use 9 KB of each device, > then reshaped THAT tiny array from 8 to 9 devices, with the rest left > completely untouched. > > So you could try removing the "new" disk, then try --create --assume-clean > with old devices only and --raid-devices=8. > > But I'm not sure how you would get the device order right. > > Ideally what you can hope for, is you would get the bulk of array data intact, > only with the first 9 KB of each device *(8-2), so about the first 54 KB of > data on the md array, corrupted and unusable. It is likely the LVM and > filesystem tools will not recognize anything due to that, so you will need to > use some data recovery software to look for and save the data. > I agree with Roman. Most of your array should be still on the 8-disk layout. But you were mounted and had writing processes immediately after the broken grow, so there's probably other corruption due to writes on the 9-disk pattern in the 8 disks. Roman's suggestion is the best plan, but even after restoring LVM, expect breakage all over. Use overlays. Phil