From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bear.techie.net ([205.134.185.202]:52277 "EHLO bear.techie.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753504AbcAVOyF (ORCPT ); Fri, 22 Jan 2016 09:54:05 -0500 Date: Fri, 22 Jan 2016 09:53:55 -0500 (EST) From: Scott Talbert To: Anand Jain cc: linux-btrfs@vger.kernel.org Subject: Re: RAID1 root filesystem - same device shows up twice in 'btrfs fi show' In-Reply-To: <56A1B312.1010105@oracle.com> Message-ID: References: <56A1B312.1010105@oracle.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Fri, 22 Jan 2016, Anand Jain wrote: > Thanks for the report. > Strange. but interesting. Can you pls help to isolate... > > On 01/22/2016 03:50 AM, Scott Talbert wrote: >> 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? > > May be dev1 is known as sdf initially before bootup and later when > system boots its known as sde. > > I believe /boot is on non btrfs FS? /boot is on the btrfs rootfs, ie, /dev/sde2 / /dev/sdf2. I do have a bios_grub partition as partition #1 but not a separate /boot partition. > As this is a root device, Can you tell which "one" device is used for > the mount in fstab ? I am using the UUID to mount in fstab: UUID=49f7413a-99ad-41b0-8783-06c9406e2280 / btrfs defaults 0 1 > Do you see the following log in the bootup logs / dmesg ? > ------ > printk(KERN_INFO "BTRFS: device fsid %pU devid %llu transid %llu %s %s\n", > disk_super->fsid, devid, transid, path, > ret == 2 ? "(overwritten)":""); > ------- Interestingly, the kernel logs show both devices... [ 10.225915] BTRFS: device fsid 49f7413a-99ad-41b0-8783-06c9406e2280 devid 2 transid 1033 /dev/sdf2 [ 10.226297] BTRFS: device fsid 49f7413a-99ad-41b0-8783-06c9406e2280 devid 1 transid 1033 /dev/sde2 > Can you provide.. > blkid output /dev/sde2: UUID="49f7413a-99ad-41b0-8783-06c9406e2280" UUID_SUB="692ba0c4-05b9-4681-86c4-b4af9028a533" TYPE="btrfs" /dev/sdf2: UUID="49f7413a-99ad-41b0-8783-06c9406e2280" UUID_SUB="63ee640c-0df0-490c-bff6-91d71a246ed6" TYPE="btrfs" Thanks, Scott