From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail02.iobjects.de ([188.40.134.68]:53712 "EHLO mail02.iobjects.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753717AbcD0Q3x (ORCPT ); Wed, 27 Apr 2016 12:29:53 -0400 Received: from tux.wizards.de (pD953EFF0.dip0.t-ipconnect.de [217.83.239.240]) by mail02.iobjects.de (Postfix) with ESMTPSA id 18AAA41601A6 for ; Wed, 27 Apr 2016 18:29:51 +0200 (CEST) Received: from [192.168.100.223] (ragnarok [192.168.100.223]) by tux.wizards.de (Postfix) with ESMTP id AECC311C01D9 for ; Wed, 27 Apr 2016 18:29:50 +0200 (CEST) Subject: Re: Add device while rebalancing To: linux-btrfs References: <571DFCF2.6050604@gmail.com> <571E154C.9060604@gmail.com> <571F4CD0.9050004@gmail.com> <5720A0E8.5000407@gmail.com> From: =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= Message-ID: <5720E8FE.2000407@googlemail.com> Date: Wed, 27 Apr 2016 18:29:50 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 04/27/16 17:58, Juan Alberto Cirez wrote: > Correct me if I'm wrong but the sum total of the above seems to > suggest (at first glance) that BRTFS add several layers of complexity, > but for little real benefit (at least in the case use of btrfs at the > brick layer with a distributed filesystem on top)... This may come as a surprise, but the same can be said for every other (common) filesystem (+ device management stack) that can be used standalone. Jeff Darcy (of GlusterFS) just wrote a really nice blog post why current filesystems and their historically grown requirements (mostly as they relate to the POSIX interface standard) are in many ways just not a good fit for scale-out/redundant storage: http://pl.atyp.us/2016-05-updating-posix.html Quite a few of the capabilities & features which are useful or necessary in standalone operation (regardless of single- or multi- device setup) are *actively unhelpful* in a distributed context, which is why e.g. Ceph will soon do away with the on-disk filesystem for data, and manage metadata exclusively by itself. cheers, Holger