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