Your revo drives are using GPT and have no bios_grub partition. If you want to install grub to them ( via /dev/md127 ), you will need to correct this.
** Changed in: grub2 (Ubuntu) Status: Confirmed => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1065987 Title: error: embedding is not possible, but this is required for RAID and LVM install. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1065987/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs