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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E740C4361B for ; Thu, 17 Dec 2020 12:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 436FE23715 for ; Thu, 17 Dec 2020 12:40:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726626AbgLQMkf (ORCPT ); Thu, 17 Dec 2020 07:40:35 -0500 Received: from smtp01.belwue.de ([129.143.71.86]:45968 "EHLO smtp01.belwue.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726569AbgLQMkf (ORCPT ); Thu, 17 Dec 2020 07:40:35 -0500 X-Greylist: delayed 583 seconds by postgrey-1.27 at vger.kernel.org; Thu, 17 Dec 2020 07:40:33 EST Received: from fex.rus.uni-stuttgart.de (fex.rus.uni-stuttgart.de [129.69.1.129]) by smtp01.belwue.de (Postfix) with SMTP id A80119CD0 for ; Thu, 17 Dec 2020 13:30:08 +0100 (MET) Date: Thu, 17 Dec 2020 13:30:08 +0100 From: Ulli Horlacher To: linux-btrfs@vger.kernel.org Subject: how to extend a btrfs disk image? Message-ID: <20201217123008.GA22831@tik.uni-stuttgart.de> Mail-Followup-To: linux-btrfs@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org How can I add a second disk-image to an existing btrfs filesystem? I have to use btrfs via a disk image on a nfs Netapp storage system with a 16 TB file size limit. One cannot use bigger files. I have set up sucessfully: root@fextest:/nfs/rusnas/fex# touch disk1.btrfs root@fextest:/nfs/rusnas/fex# truncate -s 16TB disk1.btrfs root@fextest:/nfs/rusnas/fex# ll disk1.btrfs -rw-r--r-- root root 16,000,000,000,000 2020-12-17 13:18:59 disk1.btrfs root@fextest:/nfs/rusnas/fex# mkfs.btrfs disk1.btrfs btrfs-progs v5.4.1 See http://btrfs.wiki.kernel.org for more information. Label: (null) UUID: 4f7befb1-c892-497f-a40c-c6ac1a18368d Node size: 16384 Sector size: 4096 Filesystem size: 14.55TiB Block group profiles: Data: single 8.00MiB Metadata: DUP 1.00GiB System: DUP 8.00MiB SSD detected: no Incompat features: extref, skinny-metadata Checksum: crc32c Number of devices: 1 Devices: ID SIZE PATH 1 14.55TiB disk1.btrfs root@fextest:/nfs/rusnas/fex# mount disk1.btrfs /mnt/tmp root@fextest:/nfs/rusnas/fex# df -TH /mnt/tmp Filesystem Type Size Used Avail Use% Mounted on /dev/loop2 btrfs 16T 3.7M 16T 1% /mnt/tmp No problem so far, everything is easy ;-) Now I want to extend this filesystem, but this approach fails: root@fextest:/nfs/rusnas/fex# touch disk2.btrfs root@fextest:/nfs/rusnas/fex# truncate -s 16TB disk2.btrfs root@fextest:/nfs/rusnas/fex# btrfs device add /nfs/rusnas/fex/disk2.btrfs /mnt/tmp ERROR: /nfs/rusnas/fex/disk2.btrfs is not a block device root@fextest:/nfs/rusnas/fex# sysinfo System: Linux fextest 5.4.0-58-generic x86_64 Distribution: Ubuntu 20.04.1 LTS Hardware: VMware, Inc. VMware Virtual Platform None (VMware) CPU: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz, 4 x 2394 MHz RAM: 4095 MB -- Ullrich Horlacher Server und Virtualisierung Rechenzentrum TIK Universitaet Stuttgart E-Mail: horlacher@tik.uni-stuttgart.de Allmandring 30a Tel: ++49-711-68565868 70569 Stuttgart (Germany) WWW: http://www.tik.uni-stuttgart.de/ REF:<20201217123008.GA22831@tik.uni-stuttgart.de>