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 6AF19C433EF for ; Wed, 4 May 2022 10:07:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347764AbiEDKKx (ORCPT ); Wed, 4 May 2022 06:10:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347744AbiEDKKx (ORCPT ); Wed, 4 May 2022 06:10:53 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 727E824BCF for ; Wed, 4 May 2022 03:07:16 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 2EA4F210DC for ; Wed, 4 May 2022 10:07:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1651658835; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I8elQXjvO8x2zcUfIxzy+XrAl6BuYGTB1aQc/Zj2nGw=; b=U6NGNvHzaunaqqCqZxcxhFPzN29kuxRrmX+2vuX9a5kvsv3RcQ/UsYEgyZjMsAullfkVaC l65OUPGa/BQ/Fbp1hNgT0Y0Ze3bCwexQg2cjFIJ0IqjTHiakKNUH0k71WeCacjpW6R7MfZ kZk/4FxdYI1NPmHI/ZhjhJIhxGHxPZo= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 11B86131BD for ; Wed, 4 May 2022 10:07:15 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id vv2oAVNQcmLrGgAAMHmgww (envelope-from ) for ; Wed, 04 May 2022 10:07:15 +0000 Message-ID: <9129a5be-f0a2-5859-4c02-eb075d222a31@suse.com> Date: Wed, 4 May 2022 13:07:14 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: Debian Bullseye install btrfs raid1 Content-Language: en-US To: linux-btrfs@vger.kernel.org References: <20220504112315.71b41977e071f43db945687c@lucassen.org> <20220504120254.7fae6033bee9e63ed002bea9@lucassen.org> From: Nikolay Borisov In-Reply-To: <20220504120254.7fae6033bee9e63ed002bea9@lucassen.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 4.05.22 г. 13:02 ч., richard lucassen wrote: > On Wed, 4 May 2022 12:27:29 +0300 > Nikolay Borisov wrote: > >>> Question: is this newbie trying to set up an impossible config or >>> have I missed something crucial somewhere? >> >> That's the default behavior, the reasoning is if you are missing one >> device of a raid1 your data is at-risk in case the 2nd device fails. >> You can override this behavior by mounting in degraded mode, that is >> mount -odegraded > > Another thing: sda3/sdb3 is the root fs, so I need to tell grub that > it's ok to mount a degraded array (one or another way, don't know > if it's possible, I'm not a grub guru). Adding it to fstab makes > no sense as there is no fstab at that time. > > OTOH, when using md devices, the / fs is mounted as Degraded Array and > the remaining device remembers that this had happened. If the second > disk is replaced I have to add it manually using mdadm. The first disk > is "master". Using md the system boots and mounts / and thus all tools > are available to repair the array. > > The wiki explains how to repair an array, but when the array is the > root fs you will have a problem. > > So, what should I do when the / fs is degraded? In case of btrfs raid1 if you managed to mount the array degraded it's possible to add another device to the array and then run a balance operation so that you end up with 2 copies of your data. I.e I don't see a problem? Have I misunderstood you? > > R. >