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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 3658AC6786F for ; Tue, 30 Oct 2018 16:20:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDB9A20657 for ; Tue, 30 Oct 2018 16:20:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BDB9A20657 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rus.uni-stuttgart.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726679AbeJaBOL (ORCPT ); Tue, 30 Oct 2018 21:14:11 -0400 Received: from smtp01.belwue.de ([129.143.71.86]:55446 "EHLO smtp01.belwue.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726249AbeJaBOL (ORCPT ); Tue, 30 Oct 2018 21:14:11 -0400 X-Greylist: delayed 600 seconds by postgrey-1.27 at vger.kernel.org; Tue, 30 Oct 2018 21:14:09 EDT Received: from fex.rus.uni-stuttgart.de (fex.rus.uni-stuttgart.de [129.69.1.129]) by smtp01.belwue.de (Postfix) with SMTP id 490BD2E37 for ; Tue, 30 Oct 2018 17:10:03 +0100 (MET) Date: Tue, 30 Oct 2018 17:10:03 +0100 From: Ulli Horlacher To: linux-btrfs@vger.kernel.org Subject: Re: Understanding "btrfs filesystem usage" Message-ID: <20181030161003.GA25765@rus.uni-stuttgart.de> Mail-Followup-To: linux-btrfs@vger.kernel.org References: <20181029181141.GA31256@rus.uni-stuttgart.de> <85a63523-7e77-f4ca-9947-2c957c5c577a@georgianit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <85a63523-7e77-f4ca-9947-2c957c5c577a@georgianit.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon 2018-10-29 (17:57), Remi Gauvin wrote: > On 2018-10-29 02:11 PM, Ulli Horlacher wrote: > > > I want to know how many free space is left and have problems in > > interpreting the output of: > > > > btrfs filesystem usage > > btrfs filesystem df > > btrfs filesystem show > > In my not so humble opinion, the filesystem usage command has the > easiest to understand output. It' lays out all the pertinent information. > > You can clearly see 825GiB is allocated, with 494GiB used, therefore, > filesystem show is actually using the "Allocated" value as "Used". > Allocated can be thought of "Reserved For". And what is "Device unallocated"? Not reserved? > As the output of the Usage command and df command clearly show, you have > almost 400GiB space available. This is the good part :-) > The disparity between 498GiB used and 823Gib is pretty high. This is > probably the result of using an SSD with an older kernel. If your > kernel is not very recent, (sorry, I forget where this was fixed, > somewhere around 4.14 or 4.15), then consider mounting with the nossd > option. I am running kernel 4.4 (it is a Ubuntu 16.04 system) But /local is on a SSD. Should I really use nossd mount option?! > You can improve this by running a balance. > > Something like: > btrfs balance start -dusage=55 I run balance via cron weekly (adapted https://software.opensuse.org/package/btrfsmaintenance) -- 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:<85a63523-7e77-f4ca-9947-2c957c5c577a@georgianit.com>