There are two main components in this repository:
- ZFS: The ZFS repository contains a copy of the upstream OpenZFS
code which has been adapted and extended for Linux and FreeBSD. The vast majority of the core OpenZFS code is self-contained and can be used without modification.
- SPL: The SPL is a thin shim layer which is responsible for
implementing the fundamental interfaces required by OpenZFS. It’s this layer which allows OpenZFS to be used across multiple platforms. SPL used to be maintained in a separate repository, but was merged into the zfs repository in the
The first thing you’ll need to do is prepare your environment by installing a full development tool chain. In addition, development headers for both the kernel and the following packages must be available. It is important to note that if the development kernel headers for the currently running kernel aren’t installed, the modules won’t compile properly.
The following dependencies should be installed to build the latest ZFS 2.1 release.
sudo yum install epel-release gcc make autoconf automake libtool rpm-build libtirpc-devel libblkid-devel libuuid-devel libudev-devel openssl-devel zlib-devel libaio-devel libattr-devel elfutils-libelf-devel kernel-devel-$(uname -r) python python2-devel python-setuptools python-cffi libffi-devel git ncompress libcurl-devel sudo yum install --enablerepo=epel python-packaging dkms
RHEL/CentOS 8, Fedora:
sudo dnf install --skip-broken epel-release gcc make autoconf automake libtool rpm-build libtirpc-devel libblkid-devel libuuid-devel libudev-devel openssl-devel zlib-devel libaio-devel libattr-devel elfutils-libelf-devel kernel-devel-$(uname -r) python3 python3-devel python3-setuptools python3-cffi libffi-devel git ncompress libcurl-devel sudo dnf install --skip-broken --enablerepo=epel --enablerepo=powertools python3-packaging dkms
sudo apt install build-essential autoconf automake libtool gawk alien fakeroot dkms libblkid-dev uuid-dev libudev-dev libssl-dev zlib1g-dev libaio-dev libattr1-dev libelf-dev linux-headers-$(uname -r) python3 python3-dev python3-setuptools python3-cffi libffi-dev python3-packaging git libcurl4-openssl-dev
There are two options for building OpenZFS; the correct one largely depends on your requirements.
Packages: Often it can be useful to build custom packages from git which can be installed on a system. This is the best way to perform integration testing with systemd, dracut, and udev. The downside to using packages it is greatly increases the time required to build, install, and test a change.
- In-tree: Development can be done entirely in the SPL/ZFS source
tree. This speeds up development by allowing developers to rapidly iterate on a patch. When working in-tree developers can leverage incremental builds, load/unload kernel modules, execute utilities, and verify all their changes with the ZFS Test Suite.
The remainder of this page focuses on the in-tree option which is the recommended method of development for the majority of changes. See the custom packages page for additional information on building custom packages.
Clone from GitHub
Start by cloning the ZFS repository from GitHub. The repository has a master branch for development and a series of *-release branches for tagged releases. After checking out the repository your clone will default to the master branch. Tagged releases may be built by checking out zfs-x.y.z tags with matching version numbers or matching release branches.
git clone https://github.com/openzfs/zfs
Configure and Build
For developers working on a change always create a new topic branch based off of master. This will make it easy to open a pull request with your change latter. The master branch is kept stable with extensive regression testing of every pull request before and after it’s merged. Every effort is made to catch defects as early as possible and to keep them out of the tree. Developers should be comfortable frequently rebasing their work against the latest master branch.
In this example we’ll use the master branch and walk through a stock in-tree build. Start by checking out the desired branch then build the ZFS and SPL source in the traditional autotools fashion.
cd ./zfs git checkout master sh autogen.sh ./configure make -s -j$(nproc)
--with-linux-obj=PATHcan be passed to configure to specify a kernel installed in a non-default location. This option is also supported when building ZFS.
--enable-debugcan be set to enable all ASSERTs and additional correctness tests. This option is also supported when building ZFS.
Optional Build packages
make deb #example for Debian/Ubuntu
You can run
zfs-tests.sh without installing ZFS, see below. If you
have reason to install ZFS after building it, pay attention to how your
distribution handles kernel modules. On Ubuntu, for example, the modules
from this repository install in the
extra kernel module path, which
is not in the standard
depmod search path. Therefore, for the
duration of your testing, edit
/etc/depmod.d/ubuntu.conf and add
extra to the beginning of the search path.
You may then install using
sudo make install; sudo ldconfig; sudo depmod. You’d uninstall with
sudo make uninstall; sudo ldconfig; sudo depmod.
Running zloop.sh and zfs-tests.sh
If you wish to run the ZFS Test Suite (ZTS), then
ksh and a few
additional utilities must be installed.
sudo yum install ksh bc fio acl sysstat mdadm lsscsi parted attr nfs-utils samba rng-tools pax perf sudo yum install --enablerepo=epel dbench
RHEL/CentOS 8, Fedora:
sudo dnf install --skip-broken ksh bc fio acl sysstat mdadm lsscsi parted attr nfs-utils samba rng-tools pax perf sudo dnf install --skip-broken --enablerepo=epel dbench
sudo apt install ksh bc fio acl sysstat mdadm lsscsi parted attr dbench nfs-kernel-server samba rng-tools pax linux-perf selinux-utils quota
sudo apt install ksh bc fio acl sysstat mdadm lsscsi parted attr dbench nfs-kernel-server samba rng-tools pax linux-tools-common selinux-utils quota
There are a few helper scripts provided in the top-level scripts directory designed to aid developers working with in-tree builds.
zfs-helper.sh: Certain functionality (i.e. /dev/zvol/) depends on the ZFS provided udev helper scripts being installed on the system. This script can be used to create symlinks on the system from the installation location to the in-tree helper. These links must be in place to successfully run the ZFS Test Suite. The -i and -r options can be used to install and remove the symlinks.
sudo ./scripts/zfs-helpers.sh -i
zfs.sh: The freshly built kernel modules can be loaded using
zfs.sh. This script can later be used to unload the kernel modules with the -u option.
zloop.sh: A wrapper to run ztest repeatedly with randomized arguments. The ztest command is a user space stress test designed to detect correctness issues by concurrently running a random set of test cases. If a crash is encountered, the ztest logs, any associated vdev files, and core file (if one exists) are collected and moved to the output directory for analysis.
zfs-tests.sh: A wrapper which can be used to launch the ZFS Test Suite. Three loopback devices are created on top of sparse files located in
/var/tmp/and used for the regression test. Detailed directions for the ZFS Test Suite can be found in the README located in the top-level tests directory.
tip: The delegate tests will be skipped unless group read permission is set on the zfs directory and its parents.