From OpenZFS on OS X
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Installing the official release

Download the most recent dmg from the Downloads page.

Verify the checksums.

$ md5 OpenZFS_on_OS_X_*.dmg
$ sha1sum OpenZFS_on_OS_X_*.dmg
$ openssl dgst -sha256 OpenZFS_on_OS_X_*.dmg

Open the .dmg file.

Read ReadMe.rtf.

Start the installer by opening OpenZFS_on_OS_X_x.y.z.pkg.

Follow the prompts.

If you ever want to uninstall, follow the instructions for uninstalling a release version.

Installing from source

Initial installation from source

(Adapted from an article by ZeroBSD.)

Before doing anything else, please set your boot-args.

On OS X El Capitan (10.11), OS X Mavericks (10.9), and OS X Mountain Lion (10.8) :

sudo nvram boot-args="-v keepsyms=1"

On OS X Yosemite (10.10):

sudo nvram boot-args="-v keepsyms=1 kext-dev-mode=1"

This will take effect the next time you reboot. The argument -v will make your boot screen verbose instead of just showing the Apple logo, the argument keepsyms=1 will make your panic reports more useful for us, and the argument kext-dev-mode=1 will allow you to autoload unsigned kernel extensions from /System/Library/Extensions on OS X Yosemite. Note that kext-dev-mode is obsolete and and does nothing on OS X El Capitan. You should remove it from your boot-args to avoid confusion.

For OS X El Capitan (10.11), you also need to boot into the Recovery OS (either the Recovery partition or bootable OS X install media for 10.11) and run

csrutil disable


csrutil enable --without kext

The latter will allow you to load your custom-built, unsigned kexts, while keeping the rest of System Integrity Protection (SIP) in place. (Depending on your needs, other options you may want are --without fs, --without debug, --without dtrace, and/or --without nvram. If you specify all of them, that is approximately equivalent to csrutil disable).

If you have any other implementation of ZFS installed, you must uninstall it and reboot before proceeding further. Similarly, if you have installed the O3X installer version, please follow the uninstallation directions before proceeding.


Note: Xcode 6.3 or later is now required to build due to Broadwell CPU support requirements.

To install Homebrew:

ruby -e "$(curl -fsSL"

Paste that at a Terminal prompt.

Once Homebrew is installed, we need a couple of things first:

brew install automake libtool gawk coreutils

If you have used brew before, it might pay to check it

brew doctor

and if prompted

brew prune

Create two folders in your home directory.

mkdir -p ~/Developer ~/bin
chmod 700 ~/Developer ~/bin
chmod +a "group:everyone deny delete" ~/Developer ~/bin

Adjust your PATH variable:

echo 'export PATH=$HOME/bin:/usr/local/bin:$PATH' >> ~/.bash_profile

and update your environment by sourcing your profile.

source ~/.bash_profile

To acquire the sources and build ZFS, we can use the zfsadm script found here.

cd ~/Developer/
git clone zfsadm-repo
cp zfsadm-repo/zfsadm ~/bin/

Now you can can build OpenZFS on OS X:


This will take a few minutes, depending on your hardware. There may be some warnings during the compilation. Do not worry about it unless you see errors.

Before using ZFS, we need to actually install it. If you are a developer and wish not to install ZFS, but rather run it from the compile directory, skip ahead.

cd ~/Developer/spl
sudo make install
cd ~/Developer/zfs
sudo make install

You can check to see if the kernel extensions loaded automatically with

kextstat | grep lundman

You should see something similar to

137    1 0xffffff803f61a800 0x20c      0x20c      net.lundman.kernel.dependencies (10.0.0)
144    1 0xffffff7f82720000 0xd000     0xd000     net.lundman.spl (1.0.0) <137 7 5 4 3 1>
145    0 0xffffff7f8272d000 0x202000   0x202000   net.lundman.zfs (1.0.0) <144 13 7 5 4 3 1>

If not, make sure kextd is aware of them.

sudo touch /System/Library/Extensions
sudo killall -HUP kextd

Now check again.

kextstat | grep lundman

If not, you can load the kexts manually.

cd /System/Library/Extensions
sudo kextload spl.kext
sudo kextload -d spl.kext zfs.kext

Try running


to see if everything is installed and configured properly.

You can go ahead and create your pools at this point.

Running ZFS from the source build

In the ZFS directory there is a script called which will load the two kext modules. To run userland binaries from the source tree, use the provided script to set the DYNDL_LIBRARY_PATH variable correctly to find the libraries.

Note that will also start tail -f /var/log/system.log for your convenience.

$ sudo bash# cd ~/Developer/zfs# ./load.shkernel[0]: SPL: Loaded module v1.3.1-15_g4e2ff66 (DEBUG mode), (ncpu 4, memsize 4294967296, pages 1048576)
kernel[0]: ZFS: Loaded module v1.3.1-230_gb9658da, ZFS pool version 5000, ZFS filesystem version 5
# ./ zpool import BOOM# ./ zpool listNAME   SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
BOOM  39.8G   207M  39.5G         -     1%     0%  1.00x  ONLINE  -
# ./ zpool export BOOMUnmount successful for /Volumes/BOOM
# kextunload -b net.lundman.zfskernel[0]: ZFS: Unloaded module v1.3.1-230_gb9658da
# kextunload -b net.lundman.splkernel[0]: SPL: Released 524288 bytes from vmem_seg_arena
kernel[0]: SPL: Unloaded module. (os_mem_alloc: 0)

Upgrading a source install

When you want to get the latest commits from the GitHub, here's a quick overview of things you need to run.

First make sure you have exported all of your pools.

zpool list

For every pool listed, run

sudo zpool export $poolname

Make sure they have exported successfully.

zpool status

It should say, "no pools available."

Alternatively, you can use this script to export all pools:

if [ x$(which zpool) != x ]
	zpool list -H | awk -F '\t' '{print $1;}' | xargs -I '#' sudo zpool export '#'
	cd ~/Developer/zfs
	./ zpool list -H | awk -F '\t' '{print $1;}' | xargs -I '#' sudo ./ zpool export '#'

Get any zfsadm updates:

cd ~/Developer
[ -d zfsadm-repo/.git ] && (cd zfsadm-repo ; git pull)
[ ! -d zfsadm-repo/.git ] &&  git clone zfsadm-repo
cp zfsadm-repo/zfsadm ~/bin/

Now you should be able to upgrade your ZFS installation.

cd ~/Developer
cd spl
make clean
cd ..
cd zfs
make clean
cd ..
# Assuming the build completed successfully,
# unload the kexts. If you did not export all of
# your pools this will panic:
zfsadm -u
# Now install the upgrade.
cd spl
sudo make install
cd ..
cd zfs
sudo make install
# And verify they reloaded automatically
kextstat | grep lundman
# If not, make sure kextd is aware of them
sudo touch /System/Library/Extensions
sudo killall -HUP kextd
# and check again
kextstat | grep lundman
# if they they still have not loaded automatically
cd /System/Library/Extensions
sudo kextload spl.kext
sudo kextload -d spl.kext zfs.kext

If net.lundman.kernel.dependencies has been updated, which is rarely the case, a reboot will be necessary.

Uninstalling a source install

If you ever want to uninstall, follow the instructions for uninstalling a source install.

Using without actually installing (development)

This method is usually appropriate only for Developers.

The procedure is the same as found in the section installing from source except that you never run "make install." Instead you load the kexts manually, and execute the binaries directly from the source tree.

You can load the kexts manually by running

zfsadm -k

By default, zfsadm -k will copy spl.kext and zfs.kext from the source where they were built to /System/Library/Extensions, recursively change the ownership of everything in /System/Library/Extensions/spl.kext and /System/Library/Extensions/zfs.kext to be owned by the user "root" and the group "wheel," and then load the kexts directly from /System/Library/Extensions. If you prefer to use a different directory, use the -i option in zfsadm or edit zfsadm to hard code a different directory.

If you do not wish to use zfsadm, you can do all of this yourself, using whatever target directory you'd like. For example, you might do the following:

cd /tmp
sudo rm -rf o3x
sudo mkdir o3x
cd ~/Developer
sudo cp -r zfs/module/zfs/zfs.kext /tmp/o3x/ 
sudo cp -r spl/module/spl/spl.kext /tmp/o3x/
cd /tmp/o3x
sudo chown -R *
sudo kextload spl.kext
sudo kextload -d spl.kext zfs.kext

Once the kexts have been loaded, you can test the commands.

~/Developer/zfs/ zfs

Migrating old pools (from MacZFS or ZEVO)

First export all of your pools, and uninstall the other implementation. It is all right if you forgot to export your pools before uninstalling. You will just need to use the '-f' option when importing into OpenZFS on OS X.

To find out the pool names, you need to execute the command for pool discovery.

sudo zpool import

This will tell you what pools are available to be imported, but will not actually import anything. You can see that nothing has been imported yet by using the 'zpool status' command.

zpool status

Now that you know what pools are available to be imported, you can actually import a pool by supplying the name or guid that you saw during pool discovery.

sudo zpool import poolname (or guid)

(Notice how this differs from the command for pool discovery.)

If you forgot to export before migrating, you will need to use the '-f' option.

sudo zpool import -f poolname (or guid)

If you want to see the same information you saw during pool discovery, you will now need to use 'zpool status' rather than 'zpool import'.

zpool status

If all pools have been imported, the pool discovery command— 'zpool import' with no pool or guid specified— will return without any output.

sudo zpool import