From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bear.techie.net ([205.134.185.202]:42787 "EHLO bear.techie.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752311AbcAUUEH (ORCPT ); Thu, 21 Jan 2016 15:04:07 -0500 Received: from bear.techie.net (localhost [127.0.0.1]) by bear.techie.net (8.14.4/8.14.4/Debian-4.1ubuntu1) with ESMTP id u0LJoSNo009780 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 21 Jan 2016 14:50:28 -0500 Received: from localhost (talbert@localhost) by bear.techie.net (8.14.4/8.14.4/Submit) with ESMTP id u0LJoRks009777 for ; Thu, 21 Jan 2016 14:50:27 -0500 Date: Thu, 21 Jan 2016 14:50:27 -0500 (EST) From: Scott Talbert To: linux-btrfs@vger.kernel.org Subject: RAID1 root filesystem - same device shows up twice in 'btrfs fi show' Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi, I'm using: Kernel 4.2.6 btrfs-progs v4.3 Debian Wheezy I have a RAID1 root filesystem with two devices. When the system initially boots up, "btrfs fi show" will show the same device twice: Label: none uuid: 49f7413a-99ad-41b0-8783-06c9406e2280 Total devices 2 FS bytes used 1.19GiB devid 1 size 7.60GiB used 3.03GiB path /dev/sdf2 devid 2 size 7.60GiB used 3.01GiB path /dev/sdf2 The filesystem seems to work fine (as best as I can tell) in this state. If I then run another "btrfs device scan", it will correct itself: Label: none uuid: 49f7413a-99ad-41b0-8783-06c9406e2280 Total devices 2 FS bytes used 1.19GiB devid 1 size 7.60GiB used 3.03GiB path /dev/sde2 devid 2 size 7.60GiB used 3.01GiB path /dev/sdf2 Any idea what might be going on here? On Debian it appears that the initial "btrfs device scan" is being done by an initramfs local-premount script where it does: modprobe btrfs /bin/btrfs device scan 2>/dev/null Does there perhaps need to be some delay between inserting the kernel module and running a scan? Thanks, Scott