From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:38300 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750834Ab3KTGfS (ORCPT ); Wed, 20 Nov 2013 01:35:18 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Vj1Nc-0005nn-4W for linux-btrfs@vger.kernel.org; Wed, 20 Nov 2013 07:35:16 +0100 Received: from cpc21-stap10-2-0-cust974.12-2.cable.virginm.net ([86.0.163.207]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 20 Nov 2013 07:35:16 +0100 Received: from m_btrfs by cpc21-stap10-2-0-cust974.12-2.cable.virginm.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 20 Nov 2013 07:35:16 +0100 To: linux-btrfs@vger.kernel.org From: Martin Subject: Re: Actual effect of mkfs.btrfs -m raid10 ... -d raid10 ... Date: Wed, 20 Nov 2013 06:35:01 +0000 Message-ID: References: <20131119090602.GV4315@carfax.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 19/11/13 23:16, Duncan wrote: > So we have: > > 1) raid1 is exactly two copies of data, paired devices. > > 2) raid0 is a stripe exactly two devices wide (reinforced by to read a > stripe takes only two devices), so again paired devices. Which is fine for some occasions and a very good start point. However, I'm sure there is a strong wish to be able to specify n-copies of data/metadata spread across m devices. Or even to specify 'hot spares'. This would be a great to overcome the problem of a set of drives becoming "read-only" when one btrfs drive fails or is removed. (Or should we always mount with the "degraded" option?) Regards, Martin