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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 DD14CC67863 for ; Wed, 24 Oct 2018 04:53:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 98960207DD for ; Wed, 24 Oct 2018 04:53:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bgPdx8eu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 98960207DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1726773AbeJXNUV (ORCPT ); Wed, 24 Oct 2018 09:20:21 -0400 Received: from mail-lf1-f67.google.com ([209.85.167.67]:44582 "EHLO mail-lf1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726268AbeJXNUU (ORCPT ); Wed, 24 Oct 2018 09:20:20 -0400 Received: by mail-lf1-f67.google.com with SMTP id m18-v6so2885803lfl.11 for ; Tue, 23 Oct 2018 21:53:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:openpgp:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ca3QL15ZmVMZeWTr+zYDUodAGeAyx0eLglAOSK65KFI=; b=bgPdx8euFJLW7ZeDoLGL+X1mOLteMd2/tdXdXv1VJaZFB6yUY3ssDpuePoeJm2iVPo 0B9WNQjyETtFya0mDmn60PfyR2NBFgA7i1OgrqbKnFtRp5sSjOXGvz+o2uI4oomXrDgI SLOr8vMy5UuU9PB/Wz1/Ddv1uIqd4nPjBva01pvdS1CC02kQGoeEdYPKnJt5agEOZ6Ax aS2iSrgm+9in+i7y5fpnXd8woa/nZCGU0rb999Vy/UNV1xkdiLLzYI6nPfj24k4mjv/Z 4c6E8/o7aF+nKrYGbRdSj4hVaDOkE69BIhOtzE7+1qR5tJ6YWoyqdXk8jEOIHCGY/ypl lG3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=ca3QL15ZmVMZeWTr+zYDUodAGeAyx0eLglAOSK65KFI=; b=V90W/YR3dBlZrjq91GD9lWv7Ty66KuZvgGWAPmmEXhvah3g+aatKnwjp8SkjOiM9mQ MCK8mv0LQyObyc/xWFJiMP6Lux52W3H4ggohUI57fBfsftOn2e5dJg+JS8n1NpQSXkgG 5tOs+HngBi4afIVvt55pC28tzzbdwGmiSEgwlwnwUO2wYM5p3wXa9WwM4ykcuLnPR/c/ Fgtw8e63gAJ0saSDgxsddYzYcg9jfFJ3y6v4I44FvuyhKs6+wjTMLZIvWmlkDrre87PZ DIPd0hXKdj7bs6FDJ+WQKydYOn4OegmcEsssW4eUW6s0HtY4ym0eUEAJtNhZuFxfxTKu zTMw== X-Gm-Message-State: ABuFfoh8Wlfsl4cUF2dDLpBrDRv/ogWmP+X5AlviOV/ZDnUnPRR4Z9mq OAh9OaDnMMd7+s1lXNbtv1NdnsTAdo4= X-Google-Smtp-Source: ACcGV60pI4kZPoKxzP0uQJ3hTmnyvBIa/3VV39wUzJNAsQpQ1F0bGKHofzdAD6KiVLKp605SprIEuw== X-Received: by 2002:a19:5186:: with SMTP id g6mr13446958lfl.143.1540356831918; Tue, 23 Oct 2018 21:53:51 -0700 (PDT) Received: from [192.168.1.4] ([109.252.55.124]) by smtp.gmail.com with ESMTPSA id c22sm407201lfd.88.2018.10.23.21.53.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Oct 2018 21:53:50 -0700 (PDT) Subject: Re: Have 15GB missing in btrfs filesystem. To: Marc MERLIN , linux-btrfs@vger.kernel.org References: <20181024003613.q5bxmqm4hh5xbgmf@merlins.org> From: Andrei Borzenkov Openpgp: preference=signencrypt Autocrypt: addr=arvidjaar@gmail.com; prefer-encrypt=mutual; keydata= xsDiBDxiRwwRBAC3CN9wdwpVEqUGmSoqF8tWVIT4P/bLCSZLkinSZ2drsblKpdG7x+guxwts +LgI8qjf/q5Lah1TwOqzDvjHYJ1wbBauxZ03nDzSLUhD4Ms1IsqlIwyTLumQs4vcQdvLxjFs G70aDglgUSBogtaIEsiYZXl4X0j3L9fVstuz4/wXtwCg1cN/yv/eBC0tkcM1nsJXQrC5Ay8D /1aA5qPticLBpmEBxqkf0EMHuzyrFlqVw1tUjZ+Ep2LMlem8malPvfdZKEZ71W1a/XbRn8FE SOp0tUa5GwdoDXgEp1CJUn+WLurR0KPDf01E4j/PHHAoABgrqcOTcIVoNpv2gNiBySVsNGzF XTeY/Yd6vQclkqjBYONGN3r9R8bWA/0Y1j4XK61qjowRk3Iy8sBggM3PmmNRUJYgroerpcAr 2byz6wTsb3U7OzUZ1Llgisk5Qum0RN77m3I37FXlIhCmSEY7KZVzGNW3blugLHcfw/HuCB7R 1w5qiLWKK6eCQHL+BZwiU8hX3dtTq9d7WhRW5nsVPEaPqudQfMSi/Ux1kc0mQW5kcmVpIEJv cnplbmtvdiA8YXJ2aWRqYWFyQGdtYWlsLmNvbT7CZQQTEQIAJQIbAwYLCQgHAwIGFQgCCQoL BBYCAwECHgECF4AFAliWAiQCGQEACgkQR6LMutpd94wFGwCeNuQnMDxve/Fo3EvYIkAOn+zE 21cAnRCQTXd1hTgcRHfpArEd/Rcb5+SczsBNBDxiRyQQBACQtME33UHfFOCApLki4kLFrIw1 5A5asua10jm5It+hxzI9jDR9/bNEKDTKSciHnM7aRUggLwTt+6CXkMy8an+tVqGL/MvDc4/R KKlZxj39xP7wVXdt8y1ciY4ZqqZf3tmmSN9DlLcZJIOT82DaJZuvr7UJ7rLzBFbAUh4yRKaN nwADBwQAjNvMr/KBcGsV/UvxZSm/mdpvUPtcw9qmbxCrqFQoB6TmoZ7F6wp/rL3TkQ5UElPR gsG12+Dk9GgRhnnxTHCFgN1qTiZNX4YIFpNrd0au3W/Xko79L0c4/49ten5OrFI/psx53fhY vLYfkJnc62h8hiNeM6kqYa/x0BEddu92ZG7CRgQYEQIABgUCPGJHJAAKCRBHosy62l33jMhd AJ48P7WDvKLQQ5MKnn2D/TI337uA/gCgn5mnvm4SBctbhaSBgckRmgSxfwQ= Message-ID: Date: Wed, 24 Oct 2018 07:53:49 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181024003613.q5bxmqm4hh5xbgmf@merlins.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 24.10.2018 3:36, Marc MERLIN пишет: > Normally when btrfs fi show will show lost space because > your trees aren't balanced. > Balance usually reclaims that space, or most of it. > In this case, not so much. > > kernel 4.17.6: > > saruman:/mnt/btrfs_pool1# btrfs fi show . > Label: 'btrfs_pool1' uuid: fda628bc-1ca4-49c5-91c2-4260fe967a23 > Total devices 1 FS bytes used 186.89GiB > devid 1 size 228.67GiB used 207.60GiB path /dev/mapper/pool1 > > Ok, I have 21GB between used by FS and used in block layer. > > saruman:/mnt/btrfs_pool1# btrfs balance start -dusage=40 -v . > Dumping filters: flags 0x1, state 0x0, force is off > DATA (flags 0x2): balancing, usage=40 > Done, had to relocate 1 out of 210 chunks > saruman:/mnt/btrfs_pool1# btrfs balance start -musage=60 -v . > Dumping filters: flags 0x6, state 0x0, force is off > METADATA (flags 0x2): balancing, usage=60 > SYSTEM (flags 0x2): balancing, usage=60 > Done, had to relocate 4 out of 209 chunks > saruman:/mnt/btrfs_pool1# btrfs fi show . > Label: 'btrfs_pool1' uuid: fda628bc-1ca4-49c5-91c2-4260fe967a23 > Total devices 1 FS bytes used 186.91GiB > devid 1 size 228.67GiB used 205.60GiB path /dev/mapper/pool1 > > That didn't help much, delta is now 19GB > > saruman:/mnt/btrfs_pool1# btrfs balance start -dusage=80 -v . > Dumping filters: flags 0x1, state 0x0, force is off > DATA (flags 0x2): balancing, usage=80 > Done, had to relocate 8 out of 207 chunks > saruman:/mnt/btrfs_pool1# btrfs fi show . > Label: 'btrfs_pool1' uuid: fda628bc-1ca4-49c5-91c2-4260fe967a23 > Total devices 1 FS bytes used 187.03GiB > devid 1 size 228.67GiB used 201.54GiB path /dev/mapper/pool1 > > Ok, now delta is 14GB > > saruman:/mnt/btrfs_pool1# btrfs balance start -musage=80 -v . > Dumping filters: flags 0x6, state 0x0, force is off > METADATA (flags 0x2): balancing, usage=80 > SYSTEM (flags 0x2): balancing, usage=80 > Done, had to relocate 5 out of 202 chunks > saruman:/mnt/btrfs_pool1# btrfs fi show . > Label: 'btrfs_pool1' uuid: fda628bc-1ca4-49c5-91c2-4260fe967a23 > Total devices 1 FS bytes used 188.24GiB > devid 1 size 228.67GiB used 203.54GiB path /dev/mapper/pool1 > > and it's back to 15GB :-/ > > How can I get 188.24 and 203.54 to converge further? Where is all that > space gone? > Most likely this is due to partially used extents which has been explained more than once on this list. When large extent is partially overwritten, extent is not physically split - it remains allocated in full but only part of it is referenced. Balance does not change it (at least that is my understanding) - it moves extents, but here we have internal fragmentation inside of extent. Defragmentation should rewrite files, but if you have snapshots, it is unclear if there will be any gain. I wonder if there is any tool that can compute physical vs. logical space consumption (i.e. how much space in extent is actually referenced). Should be possible using python-btrfs but probably time consuming as it needs to walk each extent.