BCacheFS is an awesome new Copy on Write (COW) filesystem created and developed by Kent Overstreet. This is a guide for installing bcachefs on Ubuntu.
The filesystem has some useful features, including (from bcachefs.org):
- Copy on Write
- Full data and metadata checksumming
- multiple devices, including replication and other types of RAID
- Scalable – has been tested to 50+TB, will eventually scale far higher
- Already working and stable, with a small community of users
Installing BCacheFS, however, is no small feat. I had pretty much given up on the endeavor until I found a Reddit post highlighting the steps. I’m mainly copying that here for posterity, fearing that the user may delete their posts in the future.
Edit the sources.list
$ sudo nano /etc/apt/sources.list
Uncomment the deb-src lines and the universe and multiverse ones as well
deb http://ca.archive.ubuntu.com/ubuntu/ bionic main restricted
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic main restricted
deb http://ca.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
deb http://ca.archive.ubuntu.com/ubuntu/ bionic universe
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic universe
deb http://ca.archive.ubuntu.com/ubuntu/ bionic-updates universe
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic-updates universe
deb http://ca.archive.ubuntu.com/ubuntu/ bionic multiverse
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://ca.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
deb http://ca.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://ca.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
Now update your package list
$ sudo apt update
Install the necessary dependencies:
$ sudo apt install devscripts gcc git libaio-dev libattr1-dev libblkid-dev libkeyutils-dev liblz4-dev libscrypt-dev libsodium-dev liburcu-dev libzstd-dev make pkg-config uuid-dev zlib1g-dev
sudo apt build-dep linux
Grab the bcachefs and bcache-tools source code:
$ git clone https://evilpiepirate.org/git/bcachefs-tools.git
$ git clone https://evilpiepirate.org/git/bcachefs.git
Build the bcachefs userspace utility
$ cd bcachefs-tools make deb cd ..
Get your kernel config:
There are plenty of different ways to configure the kernel, but I would recommend either grabbing a kernel config from one of the Ubuntu Mainline Builds or grab one of your existing configs from /boot/config-*
You just have to download the linux-headers-*-generic_*_amd64.deb file and extract it somewhere. Inside that, you’ll need to extract the data.tar file. You’ll want to copy the /./usr/src/linux-headers-*-generic/.config file.
Then just copy the .config into the bcachefs directory.
Configure the kernel
This will ask you a few questions about how your want to configure your kernel.
$ cd bcachefs
$ make oldconfig
bcachefs filesystem support (BCACHEFS_FS) [N/m/y/?] (NEW)
Answer “y” to build Bcachefs support into the kernel, answer “m” to build bcachefs as a loadable kernel module.
bcachefs quota support (BCACHEFS_QUOTA) [N/y/?] (NEW)
Answer “y” if you plan to use disk quotas, otherwise you can answer “n”.
bcachefs POSIX ACL support (BCACHEFS_POSIX_ACL) [N/y/?] (NEW)
Answer “y” if you plan to use access control lists, otherwise you can answer “n”.
Finally, there are a couple more questions about development-related options, but I usually leave them off.
Build the kernel
$ make bindeb-pkg
Or optionally, build the kernel using 3 cores (jobs) and append the short git commit hash to the version (so you can easily go back and figure out what your kernel was built against).
$ make bindeb-pkg -j 8 EXTRAVERSION=-$(git rev-parse --short HEAD) LOCALVERSION=
Install your newly-built bcachefs utility and kernel
$ cd ..
$ sudo dpkg --install bcachefs-tools*.deb linux-image-4*.deb linux-libc-dev*.deb
Reboot into your new kernel
You can now try out bcachefs!
I’m assuming that you’ve already compiled and installed the bcachefs and bacachefs-tools git repos and rebooted the system according to this guide. I’m also assuming you want a UEFI install.
For this example, the drive is at /dev/sdb. You can use gparted or gnome-disks to double-check.
Open Gparted or Disks (gnome-disks) and create a new GPT partition table.
With gparted, create a 250MB FAT32 partition with 2MB before it and everything else after it. This will be
Create ~2GB EXT2 partition with everything else after that. This will be
Create one more partition of any kind to the size you want. If you have 200GB left, use it all minus what you want for swap. This will be
Create the swap partition if you want
Still using gparted, assign the flag “
esp” and “
boot” to the EFI partition. (/dev/sdb1)
Open a terminal (CTRL + ALT+ T)
sudo bcachefs format /dev/sdb3
It’ll ask you to confirm. Double check with gparted or gnome-disks to verify it’s the right one, and then enter in y.
Paste the following into the terminal (THIS ASSUMES THE DRIVE IS /dev/sdb!!!)
sudo mount /dev/sdb3 /mnt
sudo mkdir /mnt/boot
sudo mount /dev/sdb2 /mnt/boot
sudo mkdir /mnt/boot/efi
sudo mount /dev/sdb1 /mnt/boot/efi
Everything should be ready for chrooting
Installing bcachefs on Ubuntu is no small feat, but you’ve done it! You’re not finished, however. For getting the filesystem to mount on boot, see my post on that.