Here’s what I did: I bought a new 512 GB SSD to replace my old 256 GB SSD, which was getting full. I put the new SSD in an NVME to USB adapter and then booted to a Fedora 38 live USB and cloned the old drive into the new drive using dd if=/dev/nvme0n1 of=/dev/sda. Then I used gparted to expand the LUKS partition to cover the rest of the disk. I did not have to unlock the encryption for this. After that, I powered off, removed the 256 GB SSD and installed the 512 GB SSD, then booted normally. I did not erase either of the SSDs.
Now when I get into Fedora 38, GNOME Disks reports that /dev/mapper/luks-5e5f911c... is a 511 GB ext4 partition with 80 GB free, and /dev/nvme0n1p3 is a 511 GB LUKSv2 partition, but when I run df, this is what I see:
nate@redgate:~$ df / -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/luks-5e5f911c... 233G 159G 63G 72% /
What did I do wrong?
Your method is safer imo as long as you get the dd command right. Because afterwards you’ll have two bootable copies of your system. If you mess up resizing the filesystem on the new drive, just dd again from the old one.
Glad you figured it out.
rsync also gives you two bootable copies of your system. Even better, it gives you a checksum based copy of your files including permissions.