I have misread the information you've provided, so allow me to correct myself: You're running a RAID6 array, with 2 disks lost/failed. Any disk loss after that will cause data loss since you have no redundancy (2 disks died). I believe it's still possible to reassemble the array, but you only need to remove the MBR. See this page for information: http://www.cyberciti.biz/faq/linux-how-to-uninstall-grub/ dd if=/dev/null of=/dev/sdX bs=446 count=1 Before proceeding, provide the output of cat /proc/mdstat Is the array currently running degraded or is it suspended? What happened to the spare disk assigned? Did it finish resyncing before you installed grub on the wrong disk? On Thu, Dec 17, 2009 at 8:21 AM, Majed B. <majedb@xxxxxxxxx> wrote: > If your other disks are sane and you are able to run a degraded array, then > you can remove grub using dd then re-add the disk to the array. > > To clear the first 1MB of the disk: > dd if=/dev/zero of=/dev/sdx bs=1M count=1 > Replace sdx with the disk name that has grub. > > On Dec 17, 2009 6:53 AM, "Carl Karsten" <carl@xxxxxxxxxxxxxxxxx> wrote: > > I took over a box that had 1 ide boot drive, 6 sata raid drives (4 > internal, 2 external.) I believe the 2 externals were redundant, so > could be removed. so I did, and mkfs-ed them. then I installed > ubuntu to the ide, and installed grub to sda, which turns out to be > the first sata. which would be fine if the raid was on sda1, but it > is on sda, and now the raid wont' assemble. no surprise, and I do > have a backup of the data spread across 5 external drives. but before > I abandon the array, I am wondering if I can fix it by recreating > mdadm's metatdata on sda, given I have sd[bcd] to work with. > > any suggestions? > > root@dhcp128:~# mdadm --examine /dev/sd[abcd] > mdadm: No md superblock detected on /dev/sda. > /dev/sdb: > Magic : a92b4efc > Version : 00.90.00 > UUID : 8d0cf436:3fc2d2ef:93d71b24:b036cc6b > Creation Time : Wed Mar 25 21:04:08 2009 > Raid Level : raid6 > Used Dev Size : 1465137408 (1397.26 GiB 1500.30 GB) > Array Size : 5860549632 (5589.06 GiB 6001.20 GB) > Raid Devices : 6 > Total Devices : 6 > Preferred Minor : 0 > > Update Time : Tue Mar 31 23:08:02 2009 > State : clean > Active Devices : 5 > Working Devices : 6 > Failed Devices : 1 > Spare Devices : 1 > Checksum : a4fbb93a - correct > Events : 8430 > > Chunk Size : 64K > > Number Major Minor RaidDevice State > this 6 8 16 6 spare /dev/sdb > > 0 0 8 0 0 active sync /dev/sda > 1 1 8 64 1 active sync /dev/sde > 2 2 8 32 2 active sync /dev/sdc > 3 3 8 48 3 active sync /dev/sdd > 4 4 0 0 4 faulty removed > 5 5 8 80 5 active sync > 6 6 8 16 6 spare /dev/sdb > /dev/sdc: > Magic : a92b4efc > Version : 00.90.00 > UUID : 8d0cf436:3fc2d2ef:93d71b24:b036cc6b > Creation Time : Wed Mar 25 21:04:08 2009 > Raid Level : raid6 > Used Dev Size : 1465137408 (1397.26 GiB 1500.30 GB) > Array Size : 5860549632 (5589.06 GiB 6001.20 GB) > Raid Devices : 6 > Total Devices : 4 > Preferred Minor : 0 > > Update Time : Sun Jul 12 11:31:47 2009 > State : clean > Active Devices : 4 > Working Devices : 4 > Failed Devices : 2 > Spare Devices : 0 > Checksum : a59452db - correct > Events : 580158 > > Chunk Size : 64K > > Number Major Minor RaidDevice State > this 2 8 32 2 active sync /dev/sdc > > 0 0 8 0 0 active sync /dev/sda > 1 1 0 0 1 faulty removed > 2 2 8 32 2 active sync /dev/sdc > 3 3 8 48 3 active sync /dev/sdd > 4 4 0 0 4 faulty removed > 5 5 8 96 5 active sync > /dev/sdd: > Magic : a92b4efc > Version : 00.90.00 > UUID : 8d0cf436:3fc2d2ef:93d71b24:b036cc6b > Creation Time : Wed Mar 25 21:04:08 2009 > Raid Level : raid6 > Used Dev Size : 1465137408 (1397.26 GiB 1500.30 GB) > Array Size : 5860549632 (5589.06 GiB 6001.20 GB) > Raid Devices : 6 > Total Devices : 4 > Preferred Minor : 0 > > Update Time : Sun Jul 12 11:31:47 2009 > State : clean > Active Devices : 4 > Working Devices : 4 > Failed Devices : 2 > Spare Devices : 0 > Checksum : a59452ed - correct > Events : 580158 > > Chunk Size : 64K > > Number Major Minor RaidDevice State > this 3 8 48 3 active sync /dev/sdd > > 0 0 8 0 0 active sync /dev/sda > 1 1 0 0 1 faulty removed > 2 2 8 32 2 active sync /dev/sdc > 3 3 8 48 3 active sync /dev/sdd > 4 4 0 0 4 faulty removed > 5 5 8 96 5 active sync > > -- > Carl K > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Majed B. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
