From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: assemble vs create an array....... Date: Fri, 30 Nov 2007 20:40:18 +0300 Message-ID: <47504B02.3030700@msgid.tls.msk.ru> References: <474F869D.5040503@mpigani.org> <47502406.8080809@zeniv.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <47502406.8080809@zeniv.linux.org.uk> Sender: linux-raid-owner@vger.kernel.org To: Bryce Cc: Dragos , linux-raid@vger.kernel.org List-Id: linux-raid.ids Bryce wrote: [] > mdadm -C -l5 -n5 -c128 /dev/md0 /dev/sdf1 /dev/sde1 /dev/sdg1 /dev/sdc1 /dev/sdd1 ... > IF you don't have the configuration printout, then you're left with > exhaustive brute force searching of the combinations You're missing a very important point -- --assume-clean option. For experiments like this (trying to figure out the order of disks), you'd better ensure the data on disks isn't being changed while you try different combinations. But on each build, md always destroys one drive by re-calculating parity. You have to stop it from doing so - to not trash your data. Another option is to use one missing drive always, i.e., mdadm -C -l5 -n5 -c128 /dev/md0 /dev/sdf1 missing /dev/sdg1 /dev/sdc1 /dev/sdd1 so that the array will be degraded and no way to resync anything - this also prevents md from trashing data. /mjt