From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dexter Filmore Subject: Re: softraid and multiple distros Date: Mon, 15 May 2006 14:54:27 +0200 Message-ID: <200605151454.27974.Dexter.Filmore@gmx.de> References: <200605142000.56659.Dexter.Filmore@gmx.de> <17511.46222.221460.337788@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17511.46222.221460.337788@cse.unsw.edu.au> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Neil Brown , linux-raid@vger.kernel.org List-Id: linux-raid.ids > I always use entire disks if I want the entire disks raided (sounds > obvious, doesn't it...) I only use partitions when I want to vary the > raid layout for different parts of the disk (e.g. mirrored root, mirrored > swap, raid6 for the rest). But that certainly doesn't mean it is > wrong to use partitions for the whole disk. The idea behind this is: let's say a disk fails, and you get a replacement, but it has a different geometry or a few blocks less - won't work. Even the same disk model might vary after a while. So I made 0xfd partitions of the size (whole disk minus few megs). > > > Now the devices have all two superblocks, the one left from the first try > > which are now kinda orphaned and those now active. > > Can I trust mdadm to handle this properly on its own? > > You can tell mdadm where to look. If you want to be sure that it > won't look at entire drives, only partitions, then a line like > DEVICES /dev/[hs]d*[0-1] > in /etc/mdadm.conf might be what you want. > However as you should be listing the uuids in /etc/mdadm.conf, any Umm... yeah, should I? > superblock with an unknown uuid will easily be ignored. > > If you are relying nf 0xfd autodetect to assemble your arrays, then > obviously the entire-disk superblock will be ignored (because they > wont be in the right place in any partition). So mdadm --assemble --scan is fine for my scenario even with those orphaned superblocks. Should get me some sedatives for the day when this all explodes :P -- -----BEGIN GEEK CODE BLOCK----- Version: 3.12 GCS d--(+)@ s-:+ a- C+++(++++) UL+>++++ P+>++ L+++>++++ E-- W++ N o? K- w--(---) !O M+ V- PS++(+) PE(-) Y++ PGP t++(---)@ 5 X+(++) R+(++) tv--(+)@ b++(+++) DI+++ D G++ e* h>++ r%>* y? ------END GEEK CODE BLOCK------ http://www.stop1984.com http://www.againsttcpa.com