I'm running Proxmox on a Lenovo ThinkCentre and I decided to swap the internal 256 GB 2,5" SSD for a 500 GB NVME.
I installed the new NVME alongside the old SSD, and formated it in ext4 with a single partition. I then proceeded to 'dd /dev/sda /dev/nvme0n1' and it went through without an error.
My impression was that it would clone all content from the old drive to the new, but it wouldn't boot the new drive. I then logged in and set a boot flag via fstab a, but that only helped me boot but the system gets stuck at "waiting for root file system".
Nothing is lost as the old drive still works fine when installed but how do I complete the swap correctly so I can go NVME-only?
Just using DD like this is not doing a bit clone of your drive. What you want to do can be done with DD on a blank disk (no filesystem), but you might as well just use gparted and make it easy on yourself. Otherwise, you need make sure the source and destination disks have the exact same geometry and such...it's just more steps you seem to not want to take. Just take the easy route.
So install back both disks, make a bootable gparted stick and do the cloning from there? The new disk is basically empty save the new file system, but ofc I can just delete that.
Yeah, that'll work. Gparted should wipe the destination disk for you and set the boundaries and such. Should be super easy. You can find guides online as well.
X2 for clonezilla. I would usually go the path of the OP with one exception: this particular example. Clonezilla just works so perfectly for this effect scenario i can't imagine wasting time using anything else.