From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hubert Verstraete Subject: problems with faulty disks and superblocks 1.0, 1.1 and 1.2 Date: Thu, 31 May 2007 11:20:17 +0200 Message-ID: <465E9351.2070505@free.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello I'm having problems with a RAID-1 configuration. I cannot re-add a disk that I've failed, because each time I do this, the re-added disk is still seen as failed. After some investigations, I found that this problem only occur when I create the RAID array with superblocks 1.0, 1.1 and 1.2. With the superblock 0.90 I don't encounter this issue. Here are the commands to easily reproduce the issue mdadm -C /dev/md_d0 -e 1.0 -l 1 -n 2 -b internal -R /dev/sda /dev/sdb mdadm /dev/md_d0 -f /dev/sda mdadm /dev/md_d0 -r /dev/sda mdadm /dev/md_d0 -a /dev/sda cat /proc/mdstat The output of mdstat is: Personalities : [raid1] md_d0 : active raid1 sda[0](F) sdb[1] 104849 blocks super 1.2 [2/1] [_U] bitmap: 0/7 pages [0KB], 8KB chunk unused devices: I'm wondering if the way I'm failing and re-adding a disk is correct. Did I make something wrong? If I change the superblock to "-e 0.90", there's no problem with this set of commands. For now, I found a work-around with superblock 1.0 which consists in zeroing the superblock before re-adding the disk. But I suppose that doing so will force a full rebuild of the re-added disk, and I don't want this, because I'm using write-intent bitmaps. I'm using mdadm - v2.5.6 on Debian Etch with kernel 2.6.18-4. Bug or misunderstanding from myself? Any help would be appreciated :) Thanks Hubert