From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:40469 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750969AbaCXVwl (ORCPT ); Mon, 24 Mar 2014 17:52:41 -0400 Date: Mon, 24 Mar 2014 14:52:39 -0700 From: Marc MERLIN To: Martin Cc: linux-btrfs@vger.kernel.org Subject: Re: Btrfs and raid5 status with kernel 3.14, documentation, and howto Message-ID: <20140324215239.GC11533@merlins.org> References: <20140323225657.GA17039@merlins.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Mar 24, 2014 at 07:17:12PM +0000, Martin wrote: > Thanks for the very good summary. > > So... In very brief summary, btrfs raid5 is very much a work in progress. If you know how to use it, which I didn't know do now, it's technically very usable as is. The corner cases are in having a failing drive which you can't hot remove because you can't write to it. It's unfortunate that you can't just "kill" a drive without umounting, making the drive disappear so that btrfs can't see it (dmsetup remove cryptname for me, so it's easy to do remotely), and remounting in degraded mode. > Question: Is the raid5 going to be seamlessly part of the > error-correcting raids whereby raid5, raid6, > raid-with-n-redundant-drives are all coded as one configurable raid? I'm not sure I parse your question. As far as btrfs is concerned you can switch from non raid to raid5 to raid6 by adding a drive and rebalancing which effectively reads and re-writes all the blocks in the new format. > Also (second question): What happened to the raid naming scheme that > better described the btrfs-style of raid by explicitly numbering the > number of devices used for mirroring, striping, and error-correction? btrfs fi show kind of tells you that if you know how to read it (I didn't initially). What's missing for you? Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/