Ran into slow boot on ubuntu 18.04 with local keys for usb drives with luks the magic to avoid slow boot if usb is missing is to add the noauto option in /etc/crypttab e.g. crypt tab entry foo UUID=bar /root/.bletch luks,noauto
After many days of banging my head against how to get 18.04 installed with raid1, crypt, and lvm on new disks from alternative server iso, the crux was the 1mb bios boot partition at the beginning of both disks. Without that I’d get all the way through the install and Read more
https://tutorials.technology/tutorials/move-luks-encrypted-disk.html