From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: mdadm striped parity RAID with Advanced Format drives Date: Thu, 21 Jul 2011 06:18:07 -0500 Message-ID: <4E280AEF.4020801@hardwarefreak.com> References: <201107211011.40151.polhallen@fuckaround.org> <4E27FECE.8010201@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mikael Abrahamsson Cc: Pol Hallen , linux-raid List-Id: linux-raid.ids On 7/21/2011 5:27 AM, Mikael Abrahamsson wrote: > On Thu, 21 Jul 2011, Stan Hoeppner wrote: > >> 1. Can one create a RAID5 from bare (partition-less) AF drives and >> avoid the read-modify-write problem? > > Yes, that's what I always do. Ok, good. >> 2. Or is one required to assemble the array from properly aligned >> partitions created on each drive? > > No. Great. Ok. Pol, keep in mind that all drives must be identical size when creating an array on raw disks. You said you're now working with 6 identical WD drives so this shouldn't be an issue. After you shutdown and delete the current array, wipe all existing partitions and partition tables from these drives before creating the raw disk array. Use: ~$ dd if=/dev/zero of=/dev/sdX bs=512 count=1 Do this once for each drive, replacing 'X' with the proper letter. Then create your new RAID5 array using sd[a,b,c,d,e,f]. Good luck. -- Stan