Move BTRFS @home subvolume to hdd

General system EndeavourOS installation
2
  • Format the new partition to btrfs
  • take a read-only snapshot
  • use btrfs send/btrfs receive to send the data to the other partition
  • Take a read/write snapshot
  • Update /etc/fstab to point to the new location
  • Remount /home
  • Once it is all working, delete the old subvolumes/snapshots

That being said, I don’t think you should do that if your other drive is an SSD. There are bunch of files in /home that will benefit from the faster performance of your SSD. Instead, I would create subvolumes on the new partition for things like Documents, Downloads, Videos, Music and so on. Then mount those subvolumes at the appropriate locations. That way your data will be on the HDD but the rest of /home will be on the SSD.