bcache + LUKS

bcache_luks_tutorial.sh

# Small guide to create a LUKS disk on top of a bcache device using an SSD and HDD

# Setup
# /dev/sda cache device (SSD)
# /dev/sdb backing device (HDD)

# Create the bcache
# --block should match the sector size of the backing device
# --bucket should match the cache size of the cache device
# You can ommit these two arguments and just use the default values
make-bcache -B /dev/sdb -C /dev/sda --block 4k --bucket 2M

# Change the cache mode to `writeback` this makes a slight dent on performance
# but it improves stability
echo writeback > /sys/block/bcache0/bcache/cache_mode

# Create the LUKS device on top of the newly created bcache device /dev/bcache0
cryptsetup luksFormat /dev/bcache0 keyfile.bin
cryptsetup luksOpen --key-file keyfile.bin /dev/bcache0 storage

# Format it with your FS of choice
mkfs.btrfs /dev/mapper/storage

# Dont forge to update your /etc/crypttab and /etc/fstab to open the device on boot