From mboxrd@z Thu Jan 1 00:00:00 1970 From: Janek Kozicki Subject: Re: very degraded RAID5, or increasing capacity by adding discs Date: Tue, 9 Oct 2007 00:46:36 +0200 Message-ID: <20071009004636.112c886e@absurd> References: <20071008211313.6cd8bbb5@absurd> <470A846B.9090805@sauce.co.nz> <20071009002550.12b9b26d@absurd> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20071009002550.12b9b26d@absurd> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Janek Kozicki said: (by the date of Tue, 9 Oct 2007 00:25:50 +0200) > Richard Scobie said: (by the date of Tue, 09 Oct 2007 08:26:35 +1300) > > > No, but you can make a degraded 3 drive array, containing 2 drives and > > then add the next drive to complete it. > > > > The array can then be grown (man mdadm, GROW section), to add the fourth. > > Oh, good. Thanks, I must've been blind that I missed this. > This completely solves my problem. Uh, actually not :) My 1st 500 GB drive is full now. When I buy a 2nd one I want to create a 3-disc degraded array using just 2 discs, one of which contains unbackupable data. steps: 1. create degraded two-disc RAID5 on 1 new disc 2. copy data from old disc to new one 3. rebuild the array with old and new discs (now I have 500 GB on 2 discs) 4. GROW this array to a degraded 3 discs RAID5 (so I have 1000 GB on 2 discs) ... 5. when I buy 3rd drive I either grow the array, or just rebuild and wait with growing until I buy a 4th drive. Problems at step 4.: 'man mdadm' doesn't tell if it's possible to grow an array to a degraded array (non existant disc). Is it possible? PS: the fact, that degraded array will be unsafe for the data is an intented motivating factor for buying next drive ;) -- Janek Kozicki |