A degraded array is just missing the redundant data, not needed data, right? I am pretty sure I need all 4 disks. Is there any reason to 0 out the bytes I want replaced with good bytes? On Wed, Dec 16, 2009 at 11:21 PM, 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 > -- 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
