Comment 98 for bug 569900

I think I ran into this. Have an 11.04 system, set up ways unknown. sdc1 and sdd1 were mirrored via mdadm, and sdd failed. I replaced it with an identical drive, fdisked it, and was told that it was too small when I tried to add it back into the array.

fdisk -l /dev/sdc output:

Disk /dev/sdc: 300.1 GB, 300069052416 bytes
255 heads, 63 sectors/track, 36481 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0008dc33

   Device Boot Start End Blocks Id System
/dev/sdc1 1 36482 293035008 fd Linux raid autodetect

36481 cylinder disk, with a partition ending on non-existent cylinder 36482.

I could get it to start rebuilding by adding the entire /dev/sdd device rather than a partition, but it felt weird pairing a partition with a device. I dug around a bit on Google, and ended up here.

My "solution": sfdisk -d /dev/sdc|sfdisk --force /dev/sdd (using --force because sfdisk doesn't like the way sdc1 looks either).

That got me a clone of sdc's partition layout. It doesn't explain how it got there to start, though, or if I'm skating on thin ice overall.