Linux cp command with reflink

Tue, 11 Jul 2023 09:36:53 +0000

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.

Create Linux dm-crypt BTRFS RAID 1

Wed, 12 Feb 2020 08:35:36 +0000

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.