Creating a new disk image

Bcachefs focus exclusively on reading Bcachefs archive. The best way to create a new archive is to use the standard bcachefs tools.

sudo apt-get update
sudo apt install gcc meson ninja-build
sudo apt install make pkg-config libaio-dev libblkid-dev\
     libkeyutils-dev liblz4-dev libscrypt-dev libsodium-dev\
     liburcu-dev libzstd-dev libudev-dev uuid-dev zlib1g-dev\
     libfuse3-dev

# NB: bcachefs-pytools requires a set of system libraries to be present
# more details at https://github.com/Delaunay/bcachefs-pytools
pip install git+https://github.com/Delaunay/bcachefs-pytools

# Get the size of the disk image we want to create
SIZE=$(du -shc dataset | tail -n 1 | cut -f 1)

# Create a file with the size of your dataset
truncate -s $SIZE disk.img

# Format the file using bcachefs file format
bcachefs format\
     --block_size=4k\
     --metadata_checksum=none\
     --data_checksum=none\
     --compression=none\
     --str_hash=siphash\
     --label=LabelDEADBEEF\
     disk.img

# Create a mount point we can write to
mkdir disk_mount

# Mount our image for writing
bcachefs fusemount -s disk.img disk_mount

# copy our files to the disk image
cp -r dataset dataset_mount

# check the checksum to make sure sure the copy worked
original=$(find dataset -type f -exec md5sum {} \; | cut -d ' ' -f 1 | sort | md5sum)
backup=$(find tmp/ -type f -exec md5sum {} \; | cut -d ' ' -f 1 | sort | md5sum)

echo "$original == $backup"

# Dismount the image
fusermount3 -u dataset_mount