From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from 220-245-31-42.static.tpgi.com.au ([220.245.31.42]:33460 "EHLO smtp.sws.net.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745AbaF1AvF (ORCPT ); Fri, 27 Jun 2014 20:51:05 -0400 From: Russell Coker To: Zack Coffey Reply-To: russell@coker.com.au Cc: linux-btrfs@vger.kernel.org Subject: Re: RAID1 3+ drives Date: Sat, 28 Jun 2014 10:51 +1000 Message-ID: <10572318.CAuhDIAMDU@xev> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Fri, 27 Jun 2014 20:30:32 Zack Coffey wrote: > Can I get more protection by using more than 2 drives? > > I had an onboard RAID a few years back that would let me use RAID1 > across up to 4 drives. Currently the only RAID level that fully works in BTRFS is RAID-1 with data on 2 disks. If you have 4 disks in the array then each block will be on 2 of the disks. RAID-5/6 code mostly works but the last report I read indicated that some situations for recovery and disk replacement didn't work - presumably anyone who's afraid of multiple disks failing isn't going to want to trust BTRFS RAID-6 code at the moment. If you want to have 4 disks in a fully redundant configuration (IE you could lose 3 disks without losing any data) then the thing to do is to have 2 RAID-1 arrays with Linux software RAID and then run BTRFS RAID-1 on top of that. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/