md raid5: no valid superblock, but mdadm --examine says everything is fine
Some RAID5 clean arrays, after reboot not working
Looks like this:
Nov 28 19:00:33 kernel: md: sdc does not have a valid v1.2 superblock, not importing!
Nov 28 19:00:33 kernel: md: md_import_device returned -22
Nov 28 19:00:33 kernel: md: md0 stopped.
Nov 28 19:00:33 kernel: md: sdd does not have a valid v1.2 superblock, not importing!
Nov 28 19:00:33 kernel: md: md_import_device returned -22
Nov 28 19:00:33 kernel: md: md0 stopped.
Nov 28 19:00:33 kernel: md: sdb does not have a valid v1.2 superblock, not importing!
Nov 28 19:00:33 kernel: md: md_import_device returned -22
Nov 28 19:00:33 kernel: md: md0 stopped.
Assembling array not working or kernel panic. The same problem founded here.
How-to repair
Assemble array with --update=devicesize
mdadm --assemble --verbose /dev/md0 /dev/sdd /dev/sdc /dev/sdb --update=devicesize
Original solution founded on German Ubuntu forum and works for me.