From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from postler.lichtfels.com ([78.46.92.195]:53685 "EHLO postler.lichtfels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750877AbaIYHPT (ORCPT ); Thu, 25 Sep 2014 03:15:19 -0400 Received: from localhost (localhost [127.0.0.1]) by postler.lichtfels.com (Postfix) with ESMTP id 1596B123C9 for ; Thu, 25 Sep 2014 09:15:17 +0200 (CEST) Received: from postler.lichtfels.com ([127.0.0.1]) by localhost (postler.lichtfels.com [127.0.0.1]) (amavisd-maia, port 10024) with LMTP id 07103-03 for ; Thu, 25 Sep 2014 09:15:14 +0200 (CEST) Received: from goto.oops.intern (unknown [IPv6:2001:15c0:65ff:8742:39e4:6d8d:b8e0:3beb]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by postler.lichtfels.com (Postfix) with ESMTPSA id 9BC6A123CE for ; Thu, 25 Sep 2014 09:15:14 +0200 (CEST) Message-ID: <5423C101.8000201@xunil.at> Date: Thu, 25 Sep 2014 09:15:13 +0200 From: "Stefan G. Weichinger" Reply-To: lists@xunil.at MIME-Version: 1.0 To: linux-btrfs@vger.kernel.org Subject: Re: general thoughts and questions + general and RAID5/6 stability? References: <8D1A2626CC69D79-11FC-A2C3@webmail-va141.sysops.aol.com> <54208BBC.1000700@xunil.at> <542162A8.2010700@gmail.com> <5421706F.6070301@xunil.at> <542177BF.2000808@gmail.com> In-Reply-To: <542177BF.2000808@gmail.com> Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am 23.09.2014 um 15:38 schrieb Austin S Hemmelgarn: >> What features for example? > Well, running 'mkfs.btrfs -O list-all' with 3.16 btrfs-progs gives the > following list of features: > mixed-bg - mixed data and metadata block groups > extref - increased hard-link limit per file to 65536 > raid56 - raid56 extended format > skinny-metadata - reduced size metadata extent refs > no-holes - no explicit hole extents for files > > mixed-bg is something that you generally wouldn't want to change after > mkfs. > extref can be enabled online, and the filesystem metadata gets updated > as-needed, and dosen't provide any real performance improvement (but is > needed for some mail servers that have HUGE mail-queues) > I don't know anything about the raid56 option, but there isn't any way > to change it after mkfs. > skinyy-metadata can be changed online, and the format gets updated on > rewrite of each metadata block. This one does provide a performance > improvement (stat() in particular runs noticeably faster). You should > probably enable this if it isn't already enabled, even if you don't > recreate your filesystem. > no-holes cannot currently be changed online, and is a very recent > addition (post v3.14 btrfs-progs I believe) that provides improved > performance for sparse files (which is particularly useful if you are > doing things with fixed size virtual machine disk images). Recreating or at least "btrfstune -rx" for my rootfs would mean that I have to boot from a live medium bringing recent btrfs-progs, right? sysresccd brings btrfs-progs-3.14.2 ... that should be enough, ok? aside from that, the rootfs on my thinkpad shows these features: # ls /sys/fs/btrfs/bec7dff9-8749-4db4-9a1b-fa844cfcc36a/features/ big_metadata compress_lzo extended_iref mixed_backref So I only miss the skinny extents ... and "no-holes". Stefan