From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?VG9yIEFybmUgVmVzdGLDuA==?= Subject: Re: RAID5 in sync does not populate slots sequentially, shows array as (somewhat) faulty Date: Tue, 4 Mar 2008 11:42:39 +0100 Message-ID: <47CD279F.2070500@gmail.com> References: <47CBD62E.7040608@rabbit.us> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII"; format="flowed" Return-path: In-Reply-To: <47CD23A7.2000904@rabbit.us> References: <47CC44C7.1040304@tmr.com> References: <47CD23A7.2000904@rabbit.us> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Peter Rabbitson wrote: > After Tor Arne reported his success I figured I will simply fail/remove > sda3, scrape it clean, and will add it back. I zeroed superblocks > beforehand and also wrote zeros (dd if=/dev/zero) to the drives start > and end just to make sure everythign is off. After resync I am back at > square one - the offset of sda3 is different than everything else and > the array has one failed drive. If someone can shed some light I made > snapshots of the superblocks[1] alongside with the current output of > mdadm at http://rabbit.us/pool/md5_problem.tar.bz2. Not sure if this is at all related to your problem, but one of the things I tried was to shred all the old drives in the system that were not going to be part of the array. /dev/sda system (250GB) <-- shred /dev/sdb home (250GB) <-- shred /dev/sdc raid (750GB) /dev/sdd raid (750GB) /dev/sde raid (750GB) /dev/sdf raid (750GB) The reason I did this was because /dev/sda and /dev/sdb used to be part of a RAID1 array, but were now used as system disk and home disk respectively. I was afraid that mdadm would pick up on some of the lingering RAID superblocks on those disks when reporting, so I shredded them both using 'shred -n 1' and reinstalled. Don't know if that affected anything at all for me, since the actual problem was that I didn't wait for a full resync, but now you know :) Tor Arne > > [1] dd if=/dev/sdX3 of=sdX_sb count= bs=512 > > Here is my system config: > > root@Thesaurus:/arx/space/pool# fdisk -l /dev/sd[abcd] > > Disk /dev/sda: 400.0 GB, 400088457216 bytes > 255 heads, 63 sectors/track, 48641 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > Disk identifier: 0x00000000 > > Device Boot Start End Blocks Id System > /dev/sda1 1 7 56196 fd Linux raid > autodetect > /dev/sda2 8 507 4016250 fd Linux raid > autodetect > /dev/sda3 508 36407 288366750 83 Linux > /dev/sda4 36408 48641 98269605 83 Linux > > Disk /dev/sdb: 320.0 GB, 320072933376 bytes > 255 heads, 63 sectors/track, 38913 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > Disk identifier: 0x00000000 > > Device Boot Start End Blocks Id System > /dev/sdb1 1 7 56196 fd Linux raid > autodetect > /dev/sdb2 8 507 4016250 fd Linux raid > autodetect > /dev/sdb3 508 36407 288366750 83 Linux > /dev/sdb4 36408 38913 20129445 83 Linux > > Disk /dev/sdc: 300.0 GB, 300090728448 bytes > 255 heads, 63 sectors/track, 36483 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > Disk identifier: 0x00000000 > > Device Boot Start End Blocks Id System > /dev/sdc1 1 7 56196 fd Linux raid > autodetect > /dev/sdc2 8 507 4016250 fd Linux raid > autodetect > /dev/sdc3 508 36407 288366750 83 Linux > /dev/sdc4 36408 36483 610470 83 Linux > > Disk /dev/sdd: 300.0 GB, 300090728448 bytes > 255 heads, 63 sectors/track, 36483 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > Disk identifier: 0x00000000 > > Device Boot Start End Blocks Id System > /dev/sdd1 1 7 56196 fd Linux raid > autodetect > /dev/sdd2 8 507 4016250 fd Linux raid > autodetect > /dev/sdd3 508 36407 288366750 83 Linux > /dev/sdd4 36408 36483 610470 83 Linux > root@Thesaurus:/arx/space/pool# > > root@Thesaurus:~# cat /proc/mdstat > Personalities : [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] > md5 : active raid5 sda3[4] sdd3[3] sdc3[2] sdb3[1] > 865081344 blocks super 1.1 level 5, 2048k chunk, algorithm 2 [4/4] > [UUUU] > > md1 : active raid1 sdd1[3] sdc1[2] sdb1[1] sda1[0] > 56128 blocks [4/4] [UUUU] > > md10 : active raid10 sdd2[3] sdc2[2] sdb2[1] sda2[0] > 5353472 blocks 1024K chunks 3 far-copies [4/4] [UUUU] > > unused devices: > root@Thesaurus:~# > > > > -- > 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 http://vger.kernel.org/majordomo-info.html