On Thu, Dec 17, 2009 at 4:35 AM, Majed B. <majedb@xxxxxxxxx> wrote: > 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). right - but I am not sure if data loss has occurred, where data is the data being stored on the raid, not the raid metadata. My guess is I need to copy the raid superblock from one of the other disks (say sdb), find the byets that identify the disk and change from sdb to sda. > > 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 root@dhcp128:~# cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] unused devices: <none> > Is the array currently running degraded or is it suspended? um, not running, not sure I would call it suspended. > What happened to the spare disk assigned? I don't understand. > Did it finish resyncing > before you installed grub on the wrong disk? I think so. I am fairly sure I could assemble the array before I installed grub. > > 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. > > -- 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
