I have rebooted with udev_log=debug in /etc/udev/udev.conf. I see
Jan 21 08:15:28 box systemd-udevd[607]: sdc6: Failed to update device symlinks:
Too many levels of symbolic links
Jan 21 08:15:28 box systemd-udevd[607]: sdc6: Preserve already existing symlink
'/dev/disk/by-path/pci-0000:00:17.0-ata-2.0-part6' to '../../sdc6'
Jan 21 08:15:28 box systemd-udevd[607]: sdc6: Preserve already existing symlink
'/dev/disk/by-partuuid/7acd2c90-b372-4bfb-a517-e14d2a17e342' to '../../sdc6'
Jan 21 08:15:28 box systemd-udevd[607]: sdc6: Preserve already existing symlink
'/dev/disk/by-path/pci-0000:00:17.0-ata-2-part6' to '../../sdc6'
And the same for other partitions which are all part of a Raid1 array.
Other partitions are not impacted. So I guess this is related.
But I'm blocked now.
Help please.
Thanks
Steve