From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f41.google.com ([209.85.218.41]:35855 "EHLO mail-oi0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753832AbcJKR3y (ORCPT ); Tue, 11 Oct 2016 13:29:54 -0400 Received: by mail-oi0-f41.google.com with SMTP id m72so31874499oik.3 for ; Tue, 11 Oct 2016 10:29:03 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: ronnie sahlberg Date: Tue, 11 Oct 2016 10:29:02 -0700 Message-ID: Subject: Re: RAID system with adaption to changed number of disks To: Philip Louis Moetteli Cc: "linux-btrfs@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, Oct 11, 2016 at 8:14 AM, Philip Louis Moetteli wrote: > > Hello, > > > I have to build a RAID 6 with the following 3 requirements: You should under no circumstances use RAID5/6 for anything other than test and throw-away data. It has several known issues that will eat your data. Total data loss is a real possibility. (the capability to even create raid5/6 filesystems should imho be removed from btrfs until this changes.) > > • Use different kinds of disks with different sizes. > • When a disk fails and there's enough space, the RAID should be able to reconstruct itself out of the degraded state. Meaning, if I have e. g. a RAID with 8 disks and 1 fails, I should be able to chose to transform this in a non-degraded (!) RAID with 7 disks. > • Also the other way round: If I add a disk of what size ever, it should redistribute the data, so that it becomes a RAID with 9 disks. > > I don’t care, if I have to do it manually. > I don’t care so much about speed either. > > Is BTrFS capable of doing that? > > > Thanks a lot for your help!