From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f193.google.com ([209.85.223.193]:53018 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751354AbdJXOU0 (ORCPT ); Tue, 24 Oct 2017 10:20:26 -0400 Received: by mail-io0-f193.google.com with SMTP id f20so24026110ioj.9 for ; Tue, 24 Oct 2017 07:20:26 -0700 (PDT) Subject: Re: SLES 11 SP4: can't mount btrfs To: Andrei Borzenkov Cc: Adam Borowski , "Lentes, Bernd" , Btrfs ML References: <1844960059.7648040.1508435017395.JavaMail.zimbra@helmholtz-muenchen.de> <77b2d2c6-730e-62a5-93d1-4e40b51bc131@gmail.com> <00a601d349c8$8bde60d0$a39b2270$@helmholtz-muenchen.de> <00c501d349d2$df72aa30$9e57fe90$@helmholtz-muenchen.de> <32022214.8113126.1508586366285.JavaMail.zimbra@helmholtz-muenchen.de> <20171021180752.iqkspyi2whnm4vui@angband.pl> <5b68b633-6069-067d-5b9b-81074807ab06@gmail.com> From: "Austin S. Hemmelgarn" Message-ID: <7c8034fb-ef03-5185-eeb4-79008313d211@gmail.com> Date: Tue, 24 Oct 2017 10:20:22 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2017-10-24 10:12, Andrei Borzenkov wrote: > On Tue, Oct 24, 2017 at 2:53 PM, Austin S. Hemmelgarn > wrote: >> >> SLES (and OpenSUSE in general) does do something special though, they use >> subvolumes and qgroups to replicate multiple independent partitions (which >> is a serious pain in the arse), and they have snapshotting with snapper by >> default as well. On OpenSUSE at least you can dispense with all that crap >> by telling the installer to not enable snapshot support, not sure about SLES >> though. > > SUSE is using so many subvolumes because > a) it wants to use snapshot of operating system to enable rollback > b) data that needs to be part of snapshot includes RPM database > c) RPM database is located on /var > > So they were forced to make /var part of root subvolume and explicitly > exclude everything below /var by making it separate subvolumes. > > Fortunately it is going to change now with both RH and SUSE moving RPM > database under /usr. Which leaves you basically with / and /var as > default subvolumes. > And /tmp, and /opt, and /usr/local, etc. With /var as one subvolume, I still count at least 8. That said, the issue I have with it is not as much the number, as the choice of layout (the whole /@ crap is ridiculous), and the fact that qgroups are enabled by default and not very well documented anywhere that I could find (seriously, this needs to be better documented, it took me an hour despite my background with BTRFS and as a system administrator to figure out why I couldn't fill the disk completely anywhere to wipe free space with zeroes so I could compact the disk image for the VM I was using).