From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wols Lists Subject: Re: Migrating a RAID 5 from 4x2TB to 3x6TB ? Date: Tue, 09 Jun 2015 19:46:43 +0100 Message-ID: <55773493.3050605@youngman.org.uk> References: <167089395.613.1433791723592.JavaMail.zimbra@wieser.fr> <55767860.5000803@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55767860.5000803@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Can Jeuleers , Pierre Wieser , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 09/06/15 06:23, Can Jeuleers wrote: > On 08/06/15 21:28, Pierre Wieser wrote: >> Hi all, >> >> I currently have an almost full RAID 5 built with 4 x 2 TB disks. >> I wonder if it would be possible to migrate it to a bigger RAID 5 >> with 3 x 6TB new disks. > > I'd recommend against it: > > https://en.wikipedia.org/wiki/RAID#Unrecoverable_read_errors_during_rebuild > > Jan > Please expand! Having read the article, it doesn't seem to say anything more than what is repeated time and time on this list - MAKE SURE YOUR DRIVES ARE DECENT RAID DRIVES. If you have ERC, then the odd "soft" read error doesn't matter. If you don't have ERC, then your data is at risk when you replace a drive, and it doesn't matter how big your drives are, it's the array size that matters. Cheers, Wol