From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: RE: Requesting replace mode for changing a disk Date: Wed, 13 May 2009 14:31:03 +1000 Message-ID: <18954.19719.172893.761454@notabene.brown> References: <4A060CBE.9090308@tmr.com> <20090513012112681.IEFQ19662@cdptpa-omta02.mail.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Leslie Rhorer on Tuesday May 12 Sender: linux-raid-owner@vger.kernel.org To: lrhorer@satx.rr.com Cc: 'Linux RAID' List-Id: linux-raid.ids On Tuesday May 12, lrhorer@satx.rr.com wrote: > > But doesn't creating the array with the drive wipe the contents? If so, it > doesn't seem to me this provides much redundancy. No. Creating an array does not wipe the contents. It might cause a resync which will copy contents from one drive to the other and I don't promise which one. However if you: mdadm -C /dev/md0 --level 1 -n 2 /dev/foo missing mdadm /dev/md0 --add /dev/bar then the contents on /dev/foo will not be changed (except for a few K at the end for the metadata) and then all of foo will be copied to bar. NeilBrown