From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 8F74D138C9D for ; Tue, 28 Apr 2015 17:39:06 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 1781DE092E; Tue, 28 Apr 2015 17:38:58 +0000 (UTC) Received: from mail-ig0-f179.google.com (mail-ig0-f179.google.com [209.85.213.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 5C4B5E08BB for ; Tue, 28 Apr 2015 17:38:56 +0000 (UTC) Received: by igblo3 with SMTP id lo3so96174324igb.1 for ; Tue, 28 Apr 2015 10:38:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:content-type; bh=MTQG5Z6USPT+sEsQPHOVID8YtJLPlCuPydqj4tY3FAc=; b=BRU0Bist4zwumIFHMyqDX1n7Vaq89snskMUkAnoDNqA3NGeHpYRuuhsL64T0xljEF1 lvGRXP47g1IKdW86TbTYN0OzW+vIX/eyveLX9VzWI5OtjcPXtYSCH7o16BS/e3iNT7J6 uPJPQfvX3eLA1xk81vgr0cwG9IBQG+AMp9gWg1WAr44afnO3lTFZgPdsGkN0Jm7YNe30 MicTohCKOgCBwytsOpPq/SMk1LzD05UBeanG1xgGlh9P3EkRrMYBc0toUaGf6mPTnMXZ RVlEL2b0CrVdfSnEtXhwE3ENqaCF0zSV45R50HsTXVO0IKiPCkX8Tb6Bn1jvDXcjnvp8 /ybQ== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 X-Received: by 10.43.66.131 with SMTP id xq3mr20245744icb.9.1430242735550; Tue, 28 Apr 2015 10:38:55 -0700 (PDT) Sender: freemanrich@gmail.com Received: by 10.107.48.66 with HTTP; Tue, 28 Apr 2015 10:38:55 -0700 (PDT) In-Reply-To: <20150428162448.160e1683@digimed.co.uk> References: <553F474E.4040101@gmail.com> <553FA0DD.1090101@gmail.com> <20150428162448.160e1683@digimed.co.uk> Date: Tue, 28 Apr 2015 13:38:55 -0400 X-Google-Sender-Auth: r2W0RSs1_GTBQzG3dSadQzQw0cA Message-ID: Subject: Re: [gentoo-user] Hard drive storage questions From: Rich Freeman To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: 03d55ab8-e11e-4692-ae45-c10b39212503 X-Archives-Hash: 3378bbca0ac88b6ab8b4cdccb85e8120 On Tue, Apr 28, 2015 at 11:24 AM, Neil Bothwick wrote: > The same is also possible with BTRFS, including built in RAID. RAID5 in > btrfs is expermiental, but its RAID1 is like RAID5 in some ways, such as > giving the capacity of n-1 disks and tolerating a single disk failure. > btrfs raid5 is still fairly experimental (though now it supports recovery) and works more-or-less how you'd expect raid5 to work. Raid1 on btrfs gives you the capacity of n/2 and not n-1 disks, as you would expect. It does allow disks to be of different size, in which case it gives you up to n/2 capacity (and usually more than you'd get with traditional raid1 - it tries to fill the largest disks first so 3+1+1+1 TB will give you 3TB of storage, not 2TB as you'd get with mdadm raid1). Here is a btrfs raid1: df -h Filesystem Size Used Avail Use% Mounted on /dev/sdh2 3.2T 2.7T 477G 86% /data btrfs fi df /data Data, RAID1: total=2.93TiB, used=2.65TiB System, RAID1: total=32.00MiB, used=472.00KiB Metadata, RAID1: total=16.00GiB, used=14.08GiB GlobalReserve, single: total=512.00MiB, used=0.00B btrfs fi sho /data Label: 'datafs' uuid: cd074207-9bc3-402d-bee8-6a8c77d56959 Total devices 5 FS bytes used 2.67TiB devid 1 size 2.73TiB used 2.63TiB path /dev/sdh2 devid 2 size 931.32GiB used 832.03GiB path /dev/sda2 devid 3 size 931.32GiB used 834.00GiB path /dev/sde2 devid 4 size 931.32GiB used 832.00GiB path /dev/sdd2 devid 5 size 931.32GiB used 833.00GiB path /dev/sdb2 2.7TiB of data is stored on the array, which has nearly exhausted the space of 6.4TiB of drives (or 7TB). There are ~500GiB free, which would let me store ~250GiB of data. -- Rich