From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:21242 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753594AbbINJqQ (ORCPT ); Mon, 14 Sep 2015 05:46:16 -0400 Message-ID: <55F696F9.7090708@oracle.com> Date: Mon, 14 Sep 2015 17:44:25 +0800 From: Anand Jain MIME-Version: 1.0 To: Qu Wenruo CC: Ivan Petrovic , "linux-btrfs@vger.kernel.org" Subject: Re: unable to mount multi disk volume with recovery mode References: <55F66855.4010000@cn.fujitsu.com> In-Reply-To: <55F66855.4010000@cn.fujitsu.com> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi Qu, > Unfortunately, single mode means no duplication. > And degrade mount only works for RAID level with > duplication(DUP,RAID1/5/6/10). further to the below commit. commit 95669976bd7d30ae265db938ecb46a6b7f8cb893 Btrfs: don't consider the missing device when allocating new chunks in case of 2-disk RAID1 mounted with only one good disk, we would create Single profile and actually the created single profiles are still workable with one disk failed. And so the proposed patch below will let single profile to be mount in this context.. [PATCH 23/23] Btrfs: allow -o rw,degraded for single group profile to recover when missing disk is replaced balance convert can migrate single profiles back to RAID1 profile. Also your explanation for degraded is correct, I am ok to use a new new mount option (like auto-reduced-profile ?) if needed / confusing. Any comments / feedbacks are welcome. Thanks, Anand