I tried: root # mdadm -A /dev/md1 -v --force /dev/sdq1 /dev/sds1 /dev/sdab1 missing /dev/sdaa3 /dev/sdo1 /dev/sdu1 missing mdadm: looking for devices for /dev/md1 mdadm: no recogniseable superblock mdadm: /dev/sdq1 has no superblock - assembly aborted and: root # mdadm -A /dev/md1 -v --update=summaries --force /dev/sdq1 /dev/sds1 /dev/sdab1 missing /dev/sdaa3 /dev/sdo1 /dev/sdu1 missing mdadm: looking for devices for /dev/md1 mdadm: no recogniseable superblock mdadm: /dev/sdq1 has no superblock - assembly aborted My next idea is to use dd to copy the superblock from a working device to sdq1 and edit it for the correct index. Any thoughts? Is there a more automatic way to do this? Thanks for any help Andrew On 2005-12-01 0:05:54, Andrew Burgess aab@xxxxxxxxxxx said: > I have an 8 device raid6 array with 3 bad devices. Two > of the bad devices are recognized as spares belonging to > the array, the third device, the one that was most recently > an active sync part of the array somehow losts its superblock. > > I'd like to try running the array with each of the bad devices > and see which makes an array with the least damaged filesystem. > One problem is how to add the device without the superblock. > I want to make sure it goes into position[0] in the array and > I'm not sure how to specifiy that with mdadm. > > sdq1 is the device without the superblock, sdn1 and sde1 are > marked as spares but they were in sync recently. > > To add sdq1 as device [0] even though it has no superblock would it be enough > to specify all the devices in the right order and leave the two that I'm not > experimenting with as missing? > > mdadm -A /dev/md1 --force /dev/sdq1 /dev/sds1 /dev/sdab1 missing /dev/sdaa3 /dev/sdo1 /dev/sdu1 missing > > And to try each spare in positions [3] and [7] a similar command, even though > the superblocks on the spares say [8] and [9]? > > I want to avoid md doing any resyncing or recovery until I find the best > 'bad' device to use. > > Thanks for any help! > Andrew > > PS This all happened when I upgraded the motherboard and the kernel version > at the same time, the resulting combination worked badly with my disk controllers > causing md to think drives were bad when they really weren't. Though how the > superblock vanished on the one drive is a mystery... > > ======================================================= > > root # cat /proc/mdstat > md1 : inactive sds1[1] sde1[9] sdn1[8] sdu1[6] sdo1[5] sdaa3[4] sdab1[2] > 2051009792 blocks > > root # mdadm -A /dev/md1 > mdadm: /dev/md1 assembled from 5 drives and 2 spares - not enough to start the array. > > root # mdadm -A -v /dev/md1 2>&1 | grep added > mdadm: added /dev/sdab1 to /dev/md1 as 2 > mdadm: added /dev/sdaa3 to /dev/md1 as 4 > mdadm: added /dev/sdo1 to /dev/md1 as 5 > mdadm: added /dev/sdu1 to /dev/md1 as 6 > mdadm: added /dev/sdn1 to /dev/md1 as 8 > mdadm: added /dev/sde1 to /dev/md1 as 9 > mdadm: added /dev/sds1 to /dev/md1 as 1 > > root # mdadm -E /dev/sde1 > /dev/sde1: > Magic : a92b4efc > Version : 00.90.00 > UUID : 7fdb1d16:24896504:7df4ea3b:c7f0bf96 > Creation Time : Sat Nov 12 12:43:57 2005 > Raid Level : raid6 > Device Size : 292969216 (279.40 GiB 300.00 GB) > Raid Devices : 8 > Total Devices : 8 > Preferred Minor : 1 > > Update Time : Wed Nov 30 08:12:57 2005 > State : clean > Active Devices : 6 > Working Devices : 8 > Failed Devices : 2 > Spare Devices : 2 > Checksum : 2c0e61a6 - correct > Events : 0.930007 > > > Number Major Minor RaidDevice State > this 9 8 65 9 spare /dev/sde1 > > 0 0 65 1 0 active sync /dev/sdq1 > 1 1 65 33 1 active sync /dev/sds1 > 2 2 65 177 2 active sync /dev/sdab1 > 3 3 0 0 3 faulty removed > 4 4 65 163 4 active sync /dev/sdaa3 > 5 5 8 225 5 active sync /dev/sdo1 > 6 6 65 65 6 active sync /dev/sdu1 > 7 7 0 0 7 faulty removed > 8 8 8 209 8 spare /dev/sdn1 > 9 9 8 65 9 spare /dev/sde1 > > root # mdadm -E /dev/sdn1 > /dev/sdn1: > Magic : a92b4efc > Version : 00.90.00 > UUID : 7fdb1d16:24896504:7df4ea3b:c7f0bf96 > Creation Time : Sat Nov 12 12:43:57 2005 > Raid Level : raid6 > Device Size : 292969216 (279.40 GiB 300.00 GB) > Raid Devices : 8 > Total Devices : 8 > Preferred Minor : 1 > > Update Time : Wed Nov 30 08:12:57 2005 > State : clean > Active Devices : 6 > Working Devices : 8 > Failed Devices : 2 > Spare Devices : 2 > Checksum : 2c0e6234 - correct > Events : 0.930007 > > > Number Major Minor RaidDevice State > this 8 8 209 8 spare /dev/sdn1 > > 0 0 65 1 0 active sync /dev/sdq1 > 1 1 65 33 1 active sync /dev/sds1 > 2 2 65 177 2 active sync /dev/sdab1 > 3 3 0 0 3 faulty removed > 4 4 65 163 4 active sync /dev/sdaa3 > 5 5 8 225 5 active sync /dev/sdo1 > 6 6 65 65 6 active sync /dev/sdu1 > 7 7 0 0 7 faulty removed > 8 8 8 209 8 spare /dev/sdn1 > 9 9 8 65 9 spare /dev/sde1 > > - 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
