cp -pRv --reflink=auto /source/folder /destination/folder copy files and directories -p same as –preserve=mode,ownership,timestamps -R, -r, –recursive copy directories recursively -v verbose, show what is going on. –reflink[=WHEN] control clone/CoW copies. This just copied 169GB of files in 20 seconds. This only works on supported filesystems, so for example by “#Btrfs, #CIFS, #NFS 4.2, #OCFS2, #overlayfs, and #XFS”. See here. Explainshell tells you this.
To do this you need two empty drives, with the guide below all data on the drive will be lost if it is not empty! 1. Install cryptsetup apt-get install cryptsetup 2. Create the dm-crypt cryptsetup -y -v luksFormat /dev/sdb cryptsetup -y -v luksFormat /dev/sdc (Make sure to use the correct device. To show available devices use “lsblk”.) 3. Mount the cryptsetup disk cryptsetup luksOpen /dev/sdb disk1 cryptsetup luksOpen /dev/sdc disk2 4. Check if this was successful ls -l /dev/mapper/disk* or sudo cryptsetup -v status disk1 sudo cryptsetup -v status disk2 5. Create BTRFS volume RAID 1, this means all data and meta-data is mirrored, which means if you use 2 drives with i.e. 4TB each you can only use 4TG over all in the BTRFS mounted volume. mkfs.btrfs -m raid1 -d raid1 /dev/mapper/disk1 /dev/mapper/disk2 You could list more than two drive, for example to increase redundancy, but if you want to use more drive to increase storage you would have to use a different Raid level. ...