From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0EBAC433F5 for ; Wed, 8 Dec 2021 18:01:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238424AbhLHSFN (ORCPT ); Wed, 8 Dec 2021 13:05:13 -0500 Received: from drax.kayaks.hungrycats.org ([174.142.148.226]:44200 "EHLO drax.kayaks.hungrycats.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234813AbhLHSFN (ORCPT ); Wed, 8 Dec 2021 13:05:13 -0500 Received: by drax.kayaks.hungrycats.org (Postfix, from userid 1002) id 6807FC8926; Wed, 8 Dec 2021 13:01:40 -0500 (EST) Date: Wed, 8 Dec 2021 13:01:40 -0500 From: Zygo Blaxell To: Rory Campbell-Lange Cc: Roman Mamedov , linux-btrfs@vger.kernel.org Subject: Re: trouble replacing second disk from pair Message-ID: <20211208180140.GN17148@hungrycats.org> References: <20211208180955.170c6138@nvm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Wed, Dec 08, 2021 at 05:21:51PM +0000, Rory Campbell-Lange wrote: > On 08/12/21, Roman Mamedov (rm@romanrm.net) wrote: > > On Wed, 8 Dec 2021 12:40:14 +0000 > > Rory Campbell-Lange wrote: > > > > > We're trying to upgrade the disks in a btrfs pair, and I have successfully replaced one of them using btrfs replace. I presently have > > > > > > Label: 'btrfs-bkp' uuid: da90602a-b98e-4f0b-959a-ce431ac0cdfa > > > Total devices 2 FS bytes used 700.29GiB > > > devid 2 size 2.73TiB used 1.73TiB path /dev/mapper/cdisk4 > > > devid 3 size 2.73TiB used 1.75TiB path /dev/mapper/cdisk2 > > > > > > I'd like to get rid of cdisk2 and replace it with a new disk. > > > > > > However I'm unable to mount cdisk4 (the new disk) in degraded mode to allow me to similarly replace cdisk2 as I previously did for cdisk3. Is this because some of the data in only on cdisk2? If so I'd be grateful to > > > know how to ensure the two disks have the same data and to allow cdisk2 to be replaced. > > > > Looks like you need to ensure everything is RAID1 first: You definitely need these two: > > btrfs balance start -dconvert=raid1,soft /bkp > > btrfs balance start -mconvert=raid1,soft /bkp but not this one: > > btrfs balance start -sconvert=raid1,soft /bkp > > > > It might warn you about operating on system chunks, but I believe this still > > needs to be done. > > I wasn't able to run system chunks (-s) on btrfs 4.20.1-2 (debian) without > forcing it: > > ERROR: Refusing to explicitly operate on system chunks. > Pass --force if you really want to do that. -m implies -s. In normal use, there is never a reason to have different profiles for metadata and system, so balance refuses to do it. -s is useful to set up some scenarios for developer testing (though even that could be achieved with -mconvert=...,vrange=... without needing a special option). The manual could be clearer on this. > Happily everything worked fine after running the data and metadata balances. > > Thanks very much indeed for the advice. > > Rory