From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: Why does md3 persist after deleting and recreating the partitions? Date: Fri, 31 Dec 2010 12:07:33 +1100 Message-ID: <20101231120733.5439205c@notabene.brown> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mark Knecht Cc: Mathias =?ISO-8859-1?B?QnVy6W4=?= , Linux-RAID List-Id: linux-raid.ids On Thu, 30 Dec 2010 16:17:51 -0800 Mark Knecht w= rote: > On Thu, Dec 30, 2010 at 4:16 PM, Mathias Bur=E9n wrote: > > On 31 December 2010 00:14, Mark Knecht wrote= : > >> On Thu, Dec 30, 2010 at 4:12 PM, Mathias Bur=E9n wrote: > >>> On 31 December 2010 00:10, Mark Knecht wro= te: > >>>> Hi, > >>>> =A0 What am I forgetting to do? I had a RAID1 using sd{a,b,c}3. = I > >>>> stopped md3, removed the md3 line in /etc/mdadm.conf, deleted th= e > >>>> partitions using fdisk, and then created 5 new partitions using > >>>> sd{a,b,c,d,e}3 to get ready to do a 5 disk RAID6. The new partit= ions > >>>> are the same size as the old ones and located at the same sector > >>>> addresses. > >>>> > >>>> =A0 After rebooting, but before creating the new RAID6, I still = see md3: > >>>> > >>>> mark@c2stable ~ $ cat /proc/mdstat > >>>> Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5= ] [raid4] > >>>> md6 : active raid1 sdb6[1] sdc6[2] sda6[0] > >>>> =A0 =A0 =A0247416933 blocks super 1.1 [3/3] [UUU] > >>>> > >>>> md3 : active raid1 sdc3[2] sdb3[1] sda3[0] > >>>> =A0 =A0 =A052436096 blocks [3/3] [UUU] > >>>> > >>>> md5 : active raid1 sdc5[2] sdb5[1] sda5[0] > >>>> =A0 =A0 =A052436032 blocks [3/3] [UUU] > >>>> > >>>> unused devices: > >>>> mark@c2stable ~ $ > >>>> > >>>> > >>>> =A0 What am I doing wrong or forgetting? I would like md3 to be = totally > >>>> gone before I create a new md3 in it's place. > >>>> > >>>> Thanks, > >>>> Mark > >>>> -- > >>>> To unsubscribe from this list: send the line "unsubscribe linux-= raid" in > >>>> the body of a message to majordomo@vger.kernel.org > >>>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.= html > >>>> > >>> > >>> Erase the superblocks? Recreating partitions doesn't (usually) af= fect > >>> the data on the HDDs. > >>> > >>> // M > >>> > >> > >> Is erasing the superblocks a mdadm operation? I've not heard of th= at one before. > >> > >> Thanks, > >> Mark > >> > > > > Yes, see mdadm --misc. Like: > > > > mdadm --zero-superblock > > > > // M > > >=20 > Yes, just found that. >=20 > Can I still use /dev/md3 safely even though it's no longer in > mdadm.conf? I suspect I can? That sentence doesn't make much sense to me, so I suspect some misunder= stand is going on. So to be explicit: Use mdadm --zero-superblock /dev/sdc3 /dev/sdb3 /dev/sda3 to remove from those devices any record that they are part of any md = array. Does that clarify thing sufficienty? NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html