From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Chow Subject: Re: RAID-1 does not rebuild after hot-add Date: Tue, 05 Aug 2003 00:41:18 +0800 Sender: linux-raid-owner@vger.kernel.org Message-ID: <3F2E8CAE.7090208@shaolinmicro.com> References: <3F2D1FAC.9030905@shaolinmicro.com> <16173.43804.617586.906225@gargle.gargle.HOWL> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: To: Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids > > >I'm afraid I've got no idea what would be causing this. >I can only suggest you try a plain 2.4.21 kernel and if the problem >persists we can add some extra printk's to find out what is happening. > >NeilBrown > Actually, I will try to recompile a plain vanilla kernel 2.4.21 and see what happens. However, it seems the problem exists if the raid is created by mkraid with one of the disk set to failed-disk . Then hot adding other disks to the degraded array will cause this behaviour. I deduce it is something wrong in the superblock because I can only make a normal RAID with no failed-disk using "mkraid --force" or mdadm which will of course resync right after the raid starts. Is there any chance to record any failed disk information in RAID superblocks (I mean recording failed-disk on the good disk's superblock)? I thought it doesn't make sense but it did happen and is repeatable (you can try if you want). This it the only thing to deal with because we can never keep the already started "good" disk superblock which is previously created in a degraded mode with failed-disk. Also, I've make sure other hot add partitions have already dd'ed to zeros. Maybe, I can hexdump a copy of the superblock for you to look at. What is the offset and size of the superblock of a RAID-1 device? I am sure this can effectively solve the problem right away. regards, David Chow