From owner-freebsd-questions@freebsd.org Fri Aug 28 08:46:47 2015 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7AD869C4D36 for ; Fri, 28 Aug 2015 08:46:47 +0000 (UTC) (envelope-from fbsd@xtaz.co.uk) Received: from mail.xtaz.uk (tao.xtaz.uk [IPv6:2001:8b0:202::10]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 45A51ECA for ; Fri, 28 Aug 2015 08:46:46 +0000 (UTC) (envelope-from fbsd@xtaz.co.uk) Received: by mail.xtaz.uk (Postfix, from userid 1001) id D683220AEEB6; Fri, 28 Aug 2015 09:46:43 +0100 (BST) Date: Fri, 28 Aug 2015 09:46:43 +0100 From: Matt Smith To: Matthew Seaman Cc: freebsd-questions@freebsd.org Subject: Re: Replacing Drive with SSD Message-ID: <20150828084643.GB1274@xtaz.uk> Mail-Followup-To: Matt Smith , Matthew Seaman , freebsd-questions@freebsd.org References: <55E01DAE.1020709@infracaninophile.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <55E01DAE.1020709@infracaninophile.co.uk> User-Agent: Mutt/1.5.23 (2014-03-12) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Aug 2015 08:46:47 -0000 On Aug 28 09:37, Matthew Seaman wrote: >On 08/28/15 07:59, Doug Hardie wrote: >> I am having to replace a drive with a SSD. Normally if I were >> replacing it with another drive, I would hook up the new drive to the >> computer and just use dd to copy everything (system would be >> quiescent). Can I do the same with a SSD or does it need to be setup >> differently? This is a boot drive (i.e., the only drive in the >> system). The system is currently working fine, but the drive temp is >> starting to go up so I want to replace it before anything bad >> happens. > >Yes, SSDs look just like spinning rust drives to the system. All the >normal commands you'ld use to wrangle partitions and copy data around >will work just fine. > >You should take care to align partition boundaries on block-size >multiples -- and block sizes have tended to increase recently with the >increase in size of storage media generally. But that's not special to >SSDs. Then use dump and restore to copy your data over to each partition. > > Cheers, > > Matthew > > > I've heard a rumour that you should never use dd with SSD drives because of the wear levelling stuff. Apparently SSDs automatically make sure that data is sent to unused flash cells so that all the cells wear evenly, but if you use dd on them it makes them think that every single cell is in use which screws this up?