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[https://zfsonlinux.org/ {{PAGENAME}}] ([[wikipedia:en:{{PAGENAME}}]]) - also known as [https://openzfs.org/ OpenZFS] ([[wikipedia:en:OpenZFS]]) - is a modern filesystem which is well supported on [[NixOS]].
[https://zfsonlinux.org/ {{PAGENAME}}] ([[wikipedia:en:{{PAGENAME}}]]), also known as [https://openzfs.org/ OpenZFS] ([[wikipedia:en:OpenZFS]]), is a modern filesystem which is well supported on [[NixOS]].
[[category:filesystem]]
Besides the {{nixos:package|zfs}} package (''ZFS Filesystem Linux Kernel module'') itself, there are many packages in the ZFS ecosystem available.


There are a lot of packages for [[{{PAGENAME}}]]. For example there is the ''zfs'' package (''ZFS Filesystem Linux Kernel module'') itself.<ref>https://search.nixos.org/packages?channel=unstable&show=zfs&query=zfs</ref> But there are also a lot of packages of the [[{{PAGENAME}}]] ecosystem available.
ZFS integrates into NixOS via the {{nixos:option|boot.zfs}} and {{nixos:option|services.zfs}} options.


[[{{PAGENAME}}]] integrates into NixOS via its [[module]] system. Examples:
== Limitations ==
* ''boot.zfs''<ref>https://search.nixos.org/options?channel=unstable&query=boot.zfs</ref>
 
* ''service.zfs''<ref>https://search.nixos.org/options?channel=unstable&query=services.zfs</ref>
==== Latest Kernel compatible with ZFS ====
ZFS often does not support the latest Kernel versions. It is recommended to use an LTS Kernel version whenever possible; the NixOS default Kernel is generally suitable. See [[Linux kernel|Linux Kernel]] for more information about configuring a specific Kernel version.
 
If your config specifies a Kernel version that is not officially supported by upstream ZFS, the ZFS module will fail to evaluate with an error that the ZFS package is "broken". Upstream ZFS changed in 2.3 to refuse to build by default, regardless of Nixpkgs’ broken marking (or ignoring).
 
===== Selecting the latest ZFS-compatible Kernel =====
{{Warning|This will often result in the Kernel version going backwards as Kernel versions become end-of-life and are removed from Nixpkgs. If you need more control over the Kernel version due to hardware requirements, consider simply pinning a specific version rather than calculating it as below.}}
To use the latest ZFS-compatible Kernel currently available, the following configuration may be used.
 
<syntaxhighlight lang="nix">
{
  config,
  lib,
  pkgs,
  ...
}:
 
let
  zfsCompatibleKernelPackages = lib.filterAttrs (
    name: kernelPackages:
    (builtins.match "linux_[0-9]+_[0-9]+" name) != null
    && (builtins.tryEval kernelPackages).success
    && (!kernelPackages.${config.boot.zfs.package.kernelModuleAttribute}.meta.broken)
  ) pkgs.linuxKernel.packages;
  latestKernelPackage = lib.last (
    lib.sort (a: b: (lib.versionOlder a.kernel.version b.kernel.version)) (
      builtins.attrValues zfsCompatibleKernelPackages
    )
  );
in
{
  # Note this might jump back and forth as kernels are added or removed.
  boot.kernelPackages = latestKernelPackage;
}
</syntaxhighlight>


== Limitations ==
===== Using unstable, pre-release ZFS =====
{{Warning|Pre-release ZFS versions may be less well-tested, and may have critical bugs that may cause data loss.}}{{Warning|Running ZFS with a Kernel unsupported by upstream “is considered EXPERIMENTAL by the OpenZFS project. Even if it appears to build and run correctly, there may be bugs that can cause SERIOUS DATA LOSS.”}}
In some cases, a pre-release version of ZFS may be available that supports a newer Kernel. Use it with <code>boot.zfs.package = pkgs.zfs_unstable;</code>. Using zfs_unstable may allow the use of an unsupported Kernel; as warned above, [https://github.com/openzfs/zfs/blob/6a2f7b38442b42f4bc9a848f8de10fc792ce8d76/config/kernel.m4#L473-L487 upstream considers this experimental].


==== latestCompatibleLinuxPackages of ZFS for boot.kernelPackages ====
==== Partial support for swap on ZFS ====


Newest kernels might not be supported by ZFS yet. If you are running an newer kernel which is not yet officially supported by zfs, the zfs module will refuse to evaluate and show up as ''broken''.  Use <code>boot.kernelPackages = config.boot.zfs.package.latestCompatibleLinuxPackages;</code> to use the latest compatible kernel.
ZFS does not support swapfiles. swap devices can be used instead. Additionally, hibernation is disabled by default due to a [https://github.com/NixOS/nixpkgs/pull/208037 high risk] of data corruption. Note that even if that pull request is merged, it does not fully mitigate the risk. If you wish to enable hibernation regardless and made sure that swapfiles on ZFS are not used, set <code>boot.zfs.allowHibernation = true</code>.


==== missing support for SWAP on ZFS ====
==== Zpool not found ====


ZFS does not support swapfiles. Hibernation must be either disabled with <code><nowiki>boot.kernelParams = [ "nohibernate" ];</nowiki></code>, or be enabled with a separate, non-ZFS swap partition.
If NixOS fails to import the zpool on reboot, you may need to add <syntaxhighlight lang="nix" inline>boot.zfs.devNodes = "/dev/disk/by-path";</syntaxhighlight> or <syntaxhighlight lang="nix" inline>boot.zfs.devNodes = "/dev/disk/by-partuuid";</syntaxhighlight> to your configuration.nix file.


==== boot.zfs.devNodes in virtual machines ====
The differences can be tested by running <code>zpool import -d /dev/disk/by-id</code> when none of the pools are discovered, eg. a live iso.


If you are running within a VM and NixOS fails to import the zpool on reboot, you may need to add <syntaxhighlight lang="nix" inline>boot.zfs.devNodes = "/dev/disk/by-path";</syntaxhighlight> or <syntaxhighlight lang="nix" inline>boot.zfs.devNodes = "/dev/disk/by-partuuid";</syntaxhighlight> to your configuration.nix file.
==== ZFS conflicting with systemd ====


==== declarative mounting of ZFS datasets ====
ZFS will manage mounting non-legacy ZFS filesystems, but NixOS tries to manage mounting with systemd. ZFS native mountpoints are not managed as part of the system configuration (but better support hibernation with a separate swap partition). This can lead to conflicts if the ZFS mount service is also enabled for the same datasets.


When using legacy mountpoints (created with eg<code>zfs create -o mountpoint=legacy</code>) mountpoints must be specified with <code>fileSystems."/mount/point" = {};</code>. ZFS native mountpoints are not managed as part of the system configuration but better support hibernation with a separate swap partition. This can lead to conflicts if ZFS mount service is also enabled for the same datasets. Disable it with <code>systemd.services.zfs-mount.enable = false;</code>.
Disable the mount service with <code>systemd.services.zfs-mount.enable = false;</code> or remove the <code>fileSystems</code> entries in hardware-configuration.nix. Otherwise, use legacy mountpoints (created with e.g. <code>zfs create -o mountpoint=legacy</code>). Mountpoints must be specified with <code>fileSystems."/mount/point" = {};</code> or with <code>nixos-generate-config</code>.


== Guides ==
== Guides ==


==== '''OpenZFS Documentation for installing:''' ====
=== OpenZFS Documentation for installing ===
 
{{warning|This guide is not endorsed by NixOS and some features like immutable root do not have upstream support and could break on updates. If an issue arises while following this guide, please consult the guides support channels.}}
{{warning|This guide is not endorsed by NixOS and some features like immutable root do not have upstream support and could break on updates. If an issue arises while following this guide, please consult the guides support channels.}}


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It is about:
It is about:
* [https://openzfs.github.io/openzfs-docs/Getting%20Started/NixOS/index.html#installation enabling ZFS on an existing NixOS installation] and
* [https://openzfs.github.io/openzfs-docs/Getting%20Started/NixOS/index.html#installation Enabling ZFS on an existing NixOS installation]  
* [https://openzfs.github.io/openzfs-docs/Getting%20Started/NixOS/#root-on-zfs (installing NixOS with) Root on ZFS].
* [https://openzfs.github.io/openzfs-docs/Getting%20Started/NixOS/#root-on-zfs (Installing NixOS with) Root on ZFS].


It is not about:
It is not about:
* Give understandable, easy to follow and close to the standard installation guide instructions
* Giving understandable, easy to follow instructions which are close to the standard installation guide
* integrating ZFS into your existing config
* Integrating ZFS into your existing config
 
 
==== '''Simple nixos zfs installation''' ====


=== Simple NixOS ZFS on root installation ===
Start from here in the NixOS manual: [https://nixos.org/manual/nixos/stable/#sec-installation-manual].
Start from here in the NixOS manual: [https://nixos.org/manual/nixos/stable/#sec-installation-manual].
Under manual partitioning [https://nixos.org/manual/nixos/stable/#sec-installation-manual-partitioning] do this instead:
Under manual partitioning [https://nixos.org/manual/nixos/stable/#sec-installation-manual-partitioning] do this instead:


'''Partition your disk with an boot and an zfs partition with your favorite partition tool.'''
==== Partition the disk ====
We need the following partitions:
 
* 1G for boot partition with "boot" as the partition label (also called name in some tools) and ef00 as partition code
* 4G for a swap partition with "swap" as the partition label and 8200 as partition code. We will encrypt this with a random secret on each boot.
* The rest of disk space for zfs with "root" as the partition label and 8300 as partition code (default code)


Eg. 1G for boot partion, rest for zfs.
Reason for swap partition: ZFS does use a caching mechanism that is different from the normal Linux cache infrastructure.
In low-memory situations, ZFS therefore might need a bit longer to free up memory from its cache. The swap partition will help with that.


Example output from fdisk:
Example with gdisk using <code>/dev/nvme0n1</code> as the device (use <code>lsblk</code> to find the device</code>):


<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
sudo gdisk /dev/nvme0n1
GPT fdisk (gdisk) version 1.0.10
...
# boot partition
Command (? for help): n
Partition number (1-128, default 1):
First sector (2048-1000215182, default = 2048) or {+-}size{KMGTP}:
Last sector (2048-1000215182, default = 1000215175) or {+-}size{KMGTP}: +1G
Current type is 8300 (Linux filesystem)
Hex code or GUID (L to show codes, Enter = 8300): ef00
Changed type of partition to 'EFI system partition'


fdisk /dev/nvme0n1
# Swap partition
Command (m for help): p
Command (? for help): n
Partition number (2-128, default 2):
First sector (2099200-1000215182, default = 2099200) or {+-}size{KMGTP}:
Last sector (2099200-1000215182, default = 1000215175) or {+-}size{KMGTP}: +4G
Current type is 8300 (Linux filesystem)
Hex code or GUID (L to show codes, Enter = 8300): 8200
Changed type of partition to 'Linux swap'


Disk /dev/nvme0n1: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
# root partition
...
Command (? for help): n
Device          Start       End   Sectors  Size Type
Partition number (3-128, default 3):
/dev/nvme0n1p1   2048   2099199    2097152     1G EFI System
First sector (10487808-1000215182, default = 10487808) or {+-}size{KMGTP}:
/dev/nvme0n1p2 2099200 1953523711 1951424512 930.5G Linux filesystem
Last sector (10487808-1000215182, default = 1000215175) or {+-}size{KMGTP}:
Current type is 8300 (Linux filesystem)
Hex code or GUID (L to show codes, Enter = 8300):
Changed type of partition to 'Linux filesystem'
 
# write changes
Command (? for help): w
 
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
 
Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/nvme0n1.
The operation has completed successfully.
</syntaxhighlight>
Final partition table (<code>fdisk -l /dev/nvme0n1</code>):
<syntaxhighlight lang=bash>
Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         2099199   1024.0 MiB  EF00  EFI system partition
   2        2099200        10487807  4.0 GiB     8200  Linux swap
  3        10487808      1000215175  471.9 GiB  8300  Linux filesystem
</syntaxhighlight>
 
'''Let's use variables from now on for simplicity.''' Get the device ID in <code>/dev/disk/by-id/</code> (using {{ic|blkid}}), in our case here it is <code>nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O</code>
 
<syntaxhighlight lang=bash>
BOOT=/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part1
SWAP=/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part2
DISK=/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part3
</syntaxhighlight>
</syntaxhighlight>
'''Note:''' Remember to set boot partition (first partition) to "EFI System" type


'''Make zfs pool with encryption and mount points:'''
{{note|It is often recommended to specify the drive using the device ID/UUID to prevent incorrect configuration, but it is also possible to use the device name (e.g. /dev/sda). See also: [[#Zpool created with bus-based disk names]], [https://wiki.archlinux.org/title/Persistent_block_device_naming Persistent block device naming - ArchWiki]}}
 
==== Make a ZFS pool with encryption and mount points ====
 
{{Note|zpool config can significantly affect performance (especially the ashift option) so you may want to do some research. The ZFS tuning cheatsheet or ArchWiki is a good place to start.}}
 
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
zpool create -O encryption=on -O keyformat=passphrase -O keylocation=prompt -O compression=on -O mountpoint=none -O xattr=sa -O acltype=posixacl zpool /dev/nvme0n1p2
zpool create -O encryption=on -O keyformat=passphrase -O keylocation=prompt -O compression=zstd -O mountpoint=none -O xattr=sa -O acltype=posixacl -o ashift=12 zpool $DISK
# enter the password to decrypt the pool at boot
Enter new passphrase:
Re-enter new passphrase:
 
# Create datasets
zfs create zpool/root
zfs create zpool/nix
zfs create zpool/var
zfs create zpool/home


zfs create -o mountpoint=legacy zpool/root
# Mount root
zfs create -o mountpoint=legacy zpool/nix
mkdir -p /mnt
zfs create -o mountpoint=legacy zpool/var
mount -t zfs zpool/root /mnt -o zfsutil
zfs create -o mountpoint=legacy zpool/home


mkdir /mnt/root
# Mount nix, var, home
mount -F zfs zpool/root /mnt
mkdir /mnt/nix /mnt/var /mnt/home
mkdir /mnt/nix /mnt/var /mnt/home
 
mount -t zfs zpool/nix /mnt/nix -o zfsutil
mount -F zfs zpool/nix /mnt/nix
mount -t zfs zpool/var /mnt/var -o zfsutil
mount -F zfs zpool/var /mnt/var
mount -t zfs zpool/home /mnt/home -o zfsutil
mount -F zfs zpool/zpool /mnt/zpool
</syntaxhighlight>
</syntaxhighlight>


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</syntaxhighlight>
</syntaxhighlight>


'''Make fat filesystem on boot partition'''
==== Format boot partition and enable swap ====
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
mkfs.fat -F 32 -n boot /dev/nvme0n1p1
mkfs.fat -F 32 -n boot $BOOT
</syntaxhighlight>
</syntaxhighlight>


'''Installation:'''
<syntaxhighlight lang="bash">
 
mkswap -L swap $SWAP
Install: [https://nixos.org/manual/nixos/stable/#sec-installation-manual-installing]
swapon $SWAP
 
</syntaxhighlight>
Jump to "2. UEFI systems"


==== Installation ====
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Mount boot
mkdir -p /mnt/boot
mkdir -p /mnt/boot
mount /dev/disk/by-label/boot /mnt/boot
mount $BOOT /mnt/boot
 
# Generate the nixos config
nixos-generate-config --root /mnt
...
writing /mnt/etc/nixos/hardware-configuration.nix...
writing /mnt/etc/nixos/configuration.nix...
For more hardware-specific settings, see https://github.com/NixOS/nixos-hardware.
</syntaxhighlight>
</syntaxhighlight>


Jump to "4." ... /mnt/etc/nixos/configuration.nix ...
Now edit the configuration.nix that was just created in <code>/mnt/etc/nixos/configuration.nix</code> and make sure to have at least the following content in it.
 
{{file|/mnt/etc/nixos/configuration.nix|diff|3=
{
...
  # Boot loader config for configuration.nix:
  boot.loader.systemd-boot.enable = true;
 
  # for local disks that are not shared over the network, we don't need this to be random
  # without this, "ZFS requires networking.hostId to be set" will be raised
+  networking.hostId = "8425e349";
...
}
}}
 
Now check the hardware-configuration.nix in <code>/mnt/etc/nixos/hardware-configuration.nix</code> and add whats missing e.g. <code>options = [ "zfsutil" ]</code> for all filesystems except boot and <code>randomEncryption = true;</code> for the swap partition. Also change the generated swap device to the partition we created e.g. <code>/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part2</code> in this case and <code>/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part1</code> for boot.
 
{{file|/mnt/etc/nixos/configuration.nix|diff|3=
{
...
  fileSystems."/" = {
    device = "zpool/root";
    fsType = "zfs";
    # the zfsutil option is needed when mounting zfs datasets without "legacy" mountpoints
+    options = [ "zfsutil" ];
  };


Continue from here and add this Boot loader config to your configuration.nix:
  fileSystems."/nix" = {
    device = "zpool/nix";
    fsType = "zfs";
+    options = [ "zfsutil" ];
  };


<syntaxhighlight lang="nix">
  fileSystems."/var" = {  
Boot loader config for configuration.nix:
     device = "zpool/var";
  boot.loader.grub = {
     fsType = "zfs";
     enable = true;
+    options = [ "zfsutil" ];
     zfsSupport = true;
  };
    efiSupport = true;
 
     efiInstallAsRemovable = true;
  fileSystems."/home" = {
     mirroredBoots = [
     device = "zpool/home";
      { devices = [ "nodev"]; path = "/boot"; }
     fsType = "zfs";
    ];
+    options = [ "zfsutil" ];
  };
 
  fileSystems."/boot" = {
  device = "/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part1";
  fsType = "vfat";
   };
   };


</syntaxhighlight>
  swapDevices = [{
+    device = "/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part2";
+    randomEncryption = true;
  }];
}
}}


'''Note:''' Remove / comment out <syntaxhighlight lang="nix" inline>boot.loader.systemd-boot.enable = true;</syntaxhighlight> config if added by<syntaxhighlight lang="nix" inline>nixos-generate-config</syntaxhighlight>
Now you may install NixOS with <code>nixos-install</code>.


== Importing on boot ==
== Importing on boot ==
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};
};
</syntaxhighlight>
</syntaxhighlight>
=== Zpool created with bus-based disk names ===
If you used bus-based disk names in the <syntaxhighlight inline>zpool create</syntaxhighlight> command, e.g., <syntaxhighlight inline>/dev/sda</syntaxhighlight>, NixOS may run into issues importing the pool if the names change. Even if the pool is able to be mounted (with <syntaxhighlight lang="nix" inline>boot.zfs.devNodes = "/dev/disk/by-partuuid";</syntaxhighlight> set), this may manifest as a <syntaxhighlight inline>FAULTED</syntaxhighlight> disk and a <syntaxhighlight inline>DEGRADED</syntaxhighlight> pool reported by <syntaxhighlight inline>zpool status</syntaxhighlight>. The fix is to re-import the pool using disk IDs:
<syntaxhighlight>
# zpool export zpool_name
# zpool import -d /dev/disk/by-id zpool_name
</syntaxhighlight>
The import setting is reflected in <syntaxhighlight inline="" lang="bash">/etc/zfs/zpool.cache</syntaxhighlight>, so it should persist through subsequent boots.
=== Zpool created with disk IDs ===
If you used disk IDs to refer to disks in the <code>zpool create</code> command, e.g., <code>/dev/disk/by-id</code>, then NixOS may consistently fail to import the pool unless <code>boot.zfs.devNodes = "/dev/disk/by-id"</code> is also set.


== Mount datasets at boot ==
== Mount datasets at boot ==
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You can tweak the interval (defaults to once a week) and which pools should be scrubbed (defaults to all).
You can tweak the interval (defaults to once a week) and which pools should be scrubbed (defaults to all).
== Remote unlock ==
== Remote unlock ==
=== Unlock encrypted zfs via ssh on boot ===
=== Unlock encrypted ZFS via SSH on boot ===


{{note|As of 22.05, rebuilding your config with the below directions may result in a situation where, if you want to revert the changes, you may need to do some pretty hairy nix-store manipulation to be able to successfully rebuild, see https://github.com/NixOS/nixpkgs/issues/101462#issuecomment-1172926129}}
{{note|As of 22.05, rebuilding your config with the below directions may result in a situation where, if you want to revert the changes, you may need to do some pretty hairy nix-store manipulation to be able to successfully rebuild, see https://github.com/NixOS/nixpkgs/issues/101462#issuecomment-1172926129}}
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</syntaxhighlight>
</syntaxhighlight>
* In order to use DHCP in the initrd, network manager must not be enabled and <syntaxhighlight lang="nix" inline>networking.useDHCP = true;</syntaxhighlight> must be set.
* In order to use DHCP in the initrd, network manager must not be enabled and <syntaxhighlight lang="nix" inline>networking.useDHCP = true;</syntaxhighlight> must be set.
* If your network card isn't started, you'll need to add the according kernel module to the kernel and initrd as well, e.g. <syntaxhighlight lang="nix">
* If your network card isn't started, you'll need to add the according Kernel module to the Kernel and initrd as well, e.g. <syntaxhighlight lang="nix">
boot.kernelModules = [ "r8169" ];
boot.kernelModules = [ "r8169" ];
boot.initrd.kernelModules = [ "r8169" ];</syntaxhighlight>
boot.initrd.kernelModules = [ "r8169" ];</syntaxhighlight>To know what kernel modules are needed, run <code>nix shell nixpkgs#pciutils --command lspci -v | grep -iA8 'network\|ethernet'</code> .


After that you can unlock your datasets using the following ssh command:
After that you can unlock your datasets using the following ssh command:
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     # Add the load-key command to the .profile
     # Add the load-key command to the .profile
     echo "zfs load-key -a; killall zfs" >> /root/.profile
     echo "zfs load-key -a; killall zfs" >> /root/.profile
     };
     '';
   };
   };
};
};
Line 272: Line 426:
== Take snapshots automatically ==
== Take snapshots automatically ==


See <code>services.sanoid</code> section in <code>man configuration.nix</code>.
See {{nixos:option|services.sanoid}} section in <code>man configuration.nix</code>.


== NFS share ==
== NFS share ==
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Then, set <code>sharenfs</code> property:
Then, set <code>sharenfs</code> property:
<syntaxhighlight lang="console">
<syntaxhighlight lang="console">
# zfs set sharenfs="ro=192.168.1.0/24,all_squash,anonuid=70,anongid=70" rpool/myData
zfs set sharenfs="ro=192.168.1.0/24,all_squash,anonuid=70,anongid=70" rpool/myData
</syntaxhighlight>
</syntaxhighlight>
For more options, see <code>man 5 exports</code>.
For more options, see <code>man 5 exports</code>.
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Todo: sharesmb property for Samba.
Todo: sharesmb property for Samba.


== Mail notification for ZFS Event Daemon ==
== Mail notifications (ZFS Event Daemon) ==


ZFS Event Daemon (zed) monitors events generated by the ZFS kernel module and runs configured tasks. It can be configured to send an email when a pool scrub is finished or a disk has failed. [https://search.nixos.org/options?query=services.zfs.zed zed options]
ZFS Event Daemon (zed) monitors events generated by the ZFS Kernel module and runs configured tasks. It can be configured to send an email when a pool scrub is finished or a disk has failed. [https://search.nixos.org/options?query=services.zfs.zed zed options]


=== Alternative 1: Enable Mail Notification without Re-compliation ===
=== Option A: enable mail notifications without re-compliation ===


First, we need to configure a mail transfer agent, the program that sends email:
First, we need to configure a mail transfer agent, the program that sends email:
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Then, configure an alias for root account. With this alias configured, all mails sent to root, such as cron job results and failed sudo login events, will be redirected to the configured email account.
Then, configure an alias for root account. With this alias configured, all mails sent to root, such as cron job results and failed sudo login events, will be redirected to the configured email account.


<syntaxhighlight lang="bash">
<syntaxhighlight lang="nix">
tee -a /etc/aliases <<EOF
{
root: user@example.com
  environment.etc.aliases.text = ''
EOF
    root: you@example.com
  '';
}
</syntaxhighlight>
</syntaxhighlight>


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</syntaxhighlight>
</syntaxhighlight>


=== Alternative 2: Rebuild ZFS with Mail Support ===
=== Option B: Rebuild ZFS with mail support ===
The <code>zfs</code> package can be rebuilt with mail features. However, please note that this will cause Nix to recompile the entire ZFS package on the computer, and on every kernel update, which could be very time-consuming on lower-end NAS systems.
The <code>zfs</code> package can be rebuilt with mail features. However, please note that this will cause Nix to recompile the entire ZFS package on the computer, and on every Kernel update, which could be very time-consuming on lower-end NAS systems.


An alternative solution that does not involve recompliation can be found above.
An alternative solution that does not involve recompliation can be found above.


The following override is needed as <code>zfs</code> is implicitly used in partition mounting:
The following override is needed as <code>zfs</code>is implicitly used in partition mounting:


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Retrieved from "https://wiki.nixos.org/wiki/ZFS"