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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[[category: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:
* ''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>


== Limitations ==
== Limitations ==


==== latestCompatibleLinuxPackages of ZFS for boot.kernelPackages ====
==== 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.


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.
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).  


==== partial support for SWAP on ZFS ====
===== 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.


ZFS does not support swapfiles. SWAP devices must 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 / after that pull request is merged, it does not fully mitigate the risk. If you wish to enable hibernation regardless, set <code>boot.zfs.allowHibernation = true</code>.
<syntaxhighlight lang="nix">
{
  config,
  lib,
  pkgs,
  ...
}:


==== boot.zfs.devNodes ====
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>
 
===== 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].


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.
==== Partial support for swap on ZFS ====


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.
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>.


==== declarative mounting of ZFS datasets ====
==== Zpool not found ====


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>.
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.


== Guides ==
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.


==== '''OpenZFS Documentation for installing''' ====
==== ZFS conflicting with systemd ====


{{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.}}
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.  


One guide for a NixOS installation with ZFS is maintained at [https://openzfs.github.io/openzfs-docs/Getting%20Started/NixOS/ OpenZFS Documentation (''Getting Started'' for ''NixOS'')]
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>.


It is about:
== Guides ==
* [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/#root-on-zfs (installing NixOS with) Root on ZFS].


It is not about:
=== Root on ZFS with disko ===
* Give understandable, easy to follow and close to the standard installation guide instructions
* integrating ZFS into your existing config


disko[https://github.com/nix-community/disko/blob/master/example/zfs.nix] can partition disks declaratively and handle mount points at install time.


==== '''Simple NixOS ZFS installation''' ====
Don't follow the Root on ZFS guide found in OpenZFS documentation. It was abandoned and has not been updated in years. See commit log for the openzfs-docs repo for details.


=== 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 your favorite partition tool.'''
==== Partition the disk ====
 
We need the following partitions:
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
* 1G for boot partition with "boot" as the partition label (also called name in some tools) and ef00 as partition code
* 10G 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.
* 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)
* The rest of disk space for zfs with "root" as the partition label and 8300 as partition code (default code)


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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.
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
sudo gdisk /dev/nvme0n1
GPT fdisk (gdisk) version 1.0.9.1
GPT fdisk (gdisk) version 1.0.10
...
...
Command (? for help): p
# boot partition
Disk /dev/nvme0n1: 500118192 sectors, 238.5 GiB
Command (? for help): n
Sector size (logical/physical): 512/512 bytes
Partition number (1-128, default 1):  
Disk identifier (GUID): CA926E8C-47F6-416A-AD1A-C2190CF5D1F8
First sector (2048-1000215182, default = 2048) or {+-}size{KMGTP}:
Partition table holds up to 128 entries
Last sector (2048-1000215182, default = 1000215175) or {+-}size{KMGTP}: +1G
Main partition table begins at sector 2 and ends at sector 33
Current type is 8300 (Linux filesystem)
First usable sector is 34, last usable sector is 500118158
Hex code or GUID (L to show codes, Enter = 8300): ef00
Partitions will be aligned on 2048-sector boundaries
Changed type of partition to 'EFI system partition'
Total free space is 2669 sectors (1.3 MiB)
 
# Swap partition
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'
 
# root partition
Command (? for help): n
Partition number (3-128, default 3):
First sector (10487808-1000215182, default = 10487808) or {+-}size{KMGTP}:
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
Number  Start (sector)    End (sector)  Size      Code  Name
   1            2048        2099199  1024.0 MiB  EF00  boot
   1            2048        2099199  1024.0 MiB  EF00  EFI system partition
   2        2099200        23070719   10.0 GiB   8200  swap
   2        2099200        10487807   4.0 GiB     8200  Linux swap
   3        23070720      500117503   227.5 GiB  8300  root
   3        10487808      1000215175   471.9 GiB  8300  Linux filesystem
</syntaxhighlight>


Command (? for help):
'''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>


'''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.}}


'''Note:''' zpool config can significantly affect performance (especially the ashift option) so you may want to do some research. The [https://jrs-s.net/2018/08/17/zfs-tuning-cheat-sheet/ ZFS tuning cheatsheet] or [https://wiki.archlinux.org/title/ZFS#Storage_pools 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=zstd -O mountpoint=none -O xattr=sa -O acltype=posixacl -o ashift=12 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/root
zfs create zpool/nix
zfs create zpool/nix
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zfs create zpool/home
zfs create zpool/home


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


<syntaxhighlight lang="bash">
mkswap -L swap $SWAP
swapon $SWAP
</syntaxhighlight>


'''Installation:'''
==== Installation ====
 
Install: [https://nixos.org/manual/nixos/stable/#sec-installation-manual-installing]
 
Jump to "2. UEFI systems"
 
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Mount boot
mkdir -p /mnt/boot
mkdir -p /mnt/boot
mount /dev/disk/by-partlabel/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.


Continue from here and add this boot loader and filesystems config to your configuration.nix:
{{file|/mnt/etc/nixos/configuration.nix|diff|3=
 
<syntaxhighlight lang="nix">
{
{
...
   # Boot loader config for configuration.nix:
   # Boot loader config for configuration.nix:
   boot.loader.systemd-boot.enable = true;
   boot.loader.systemd-boot.enable = true;


   # for local disks that are not shared over the network, we don't need this to be random
   # for local disks that are not shared over the network, we don't need this to be random
   networking.hostId = "8425e349";
   # 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."/" = {  
   fileSystems."/" = {  
     device = "zpool/root";
     device = "zpool/root";
     fsType = "zfs";
     fsType = "zfs";
     # the zfsutil option is needed when mounting zfs datasets without "legacy" mountpoints
     # the zfsutil option is needed when mounting zfs datasets without "legacy" mountpoints
    options = [ "zfsutil" ];
+    options = [ "zfsutil" ];
   };
   };


Line 157: Line 241:
     device = "zpool/nix";
     device = "zpool/nix";
     fsType = "zfs";
     fsType = "zfs";
    options = [ "zfsutil" ];
+    options = [ "zfsutil" ];
   };
   };


Line 163: Line 247:
     device = "zpool/var";
     device = "zpool/var";
     fsType = "zfs";
     fsType = "zfs";
    options = [ "zfsutil" ];
+    options = [ "zfsutil" ];
   };
   };


Line 169: Line 253:
     device = "zpool/home";
     device = "zpool/home";
     fsType = "zfs";
     fsType = "zfs";
    options = [ "zfsutil" ];
+    options = [ "zfsutil" ];
   };
   };


   fileSystems."/boot" = {  
   fileSystems."/boot" = {  
   device = "/dev/disk/by-partlabel/boot";
   device = "/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part1";
   fsType = "vfat";
   fsType = "vfat";
   };
   };


   swapDevices = [{
   swapDevices = [{
    device = "/dev/disk/by-partlabel/swap";
+    device = "/dev/disk/by-id/nvme-SKHynix_HFS512GDE9X081N_FNB6N634510106K5O-part2";
    randomEncryption = true;
+    randomEncryption = true;
   }];
   }];
}
}
</syntaxhighlight>
}}
 
Now you may install NixOS with <code>nixos-install</code>.


== Importing on boot ==
== Importing on boot ==
Line 247: Line 333:


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}}
Line 282: Line 366:
</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:
Line 335: Line 419:
== Take snapshots automatically ==
== Take snapshots automatically ==


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


== NFS share ==
== NFS share ==
Line 350: Line 434:
</syntaxhighlight>
</syntaxhighlight>
Only this line is needed. Configure firewall if necessary, as described in [[NFS]] article.
Only this line is needed. Configure firewall if necessary, as described in [[NFS]] article.
{{warning|<code>zfs share</code> or <code>sharenfs</code> does not work if the <code>mountpoint</code> is set to <code>legacy</code> (or <code>none</code>, of course). I was unable to find a source for this behaviour, but I was stuck on the problem for days, until I realized the problem.  ::Reply: sharenfs controlls what
is written into <code>/etc/exports</code>.  If ZFS does not know the mountpoint, as is the case in
mountpoint legacy or none, the contents of <code>/etc/exports</code> would be wrong}}


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>.
Line 359: Line 447:
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]


=== Alternative 1: Enable Mail Notification without Re-compliation ===
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]


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:
<syntaxhighlight lang="nix">
<syntaxhighlight lang="nix">
{
{
  age.secrets.msmtp = {
    file = "${inputs.self.outPath}/secrets/msmtp.age";
  };
  # for zed enableMail, enable sendmailSetuidWrapper
  services.mail.sendmailSetuidWrapper.enable = true;
   programs.msmtp = {
   programs.msmtp = {
     enable = true;
     enable = true;
Line 373: Line 466:
     defaults = {
     defaults = {
       aliases = "/etc/aliases";
       aliases = "/etc/aliases";
       port = 465;
       port = 587;
       tls_trust_file = "/etc/ssl/certs/ca-certificates.crt";
       auth = "plain";
       tls = "on";
       tls = "on";
      auth = "login";
       tls_starttls = "on";
       tls_starttls = "off";
     };
     };
     accounts = {
     accounts = {
       default = {
       default = {
         host = "mail.example.com";
         host = "smtp.mail.example.com";
         passwordeval = "cat /etc/emailpass.txt";
         passwordeval = "cat ${config.age.secrets.msmtp.path}";
         user = "user@example.com";
         user = "myname@example.com";
         from = "user@example.com";
         from = "myname@example.com";
       };
       };
     };
     };
Line 393: Line 485:
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: admin@example.com
  '';
}
</syntaxhighlight>
</syntaxhighlight>


Finally, override default zed settings with a custom one:
Finally, enable zed mail notification:
<syntaxhighlight lang="nix">
<syntaxhighlight lang="nix">
{
{
   services.zfs.zed.settings = {
   services.zfs.zed. = {
     ZED_DEBUG_LOG = "/tmp/zed.debug.log";
     enableMail = true;
     ZED_EMAIL_ADDR = [ "root" ];
     settings = {
    ZED_EMAIL_PROG = "${pkgs.msmtp}/bin/msmtp";
      ZED_EMAIL_ADDR = [ "root" ];
    ZED_EMAIL_OPTS = "@ADDRESS@";
      # send notification if scrub succeeds
 
      ZED_NOTIFY_VERBOSE = true;
    ZED_NOTIFY_INTERVAL_SECS = 3600;
     };
    ZED_NOTIFY_VERBOSE = true;
 
     ZED_USE_ENCLOSURE_LEDS = true;
    ZED_SCRUB_AFTER_RESILVER = true;
   };
   };
  # this option does not work; will return error
  services.zfs.zed.enableMail = false;
}
}
</syntaxhighlight>
</syntaxhighlight>
Line 424: Line 512:
</syntaxhighlight>
</syntaxhighlight>


=== Alternative 2: 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.
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:
<syntaxhighlight lang="nix">
nixpkgs.config.packageOverrides = pkgs: {
  zfsStable = pkgs.zfsStable.override { enableMail = true; };
};
</syntaxhighlight>
A mail sender like [[msmtp]] or [[postfix]] is required.
A minimal, testable ZED configuration example:
<syntaxhighlight lang="nix">
services.zfs.zed.enableMail = true;
services.zfs.zed.settings = {
  ZED_EMAIL_ADDR = [ "root" ];
  ZED_NOTIFY_VERBOSE = true;
};
</syntaxhighlight>
Above, <code>ZED_EMAIL_ADDR</code> is set to <code>root</code>, which most people will have an alias for in their mailer. You can change it to directly mail you: <code>ZED_EMAIL_ADDR = [ "you@example.com" ];</code>
ZED pulls in <code>mailutils</code> and runs <code>mail</code> by default, but you can override it with <code>ZED_EMAIL_PROG</code>. If using msmtp, you may need <code>ZED_EMAIL_PROG = "${pkgs.msmtp}/bin/msmtp";</code>.
You can customize the mail command with <code>ZED_EMAIL_OPTS</code>. For example, if your upstream mail server requires a certain FROM address: <code>ZED_EMAIL_OPTS = "-r 'noreply@example.com' -s '@SUBJECT@' @ADDRESS@";</code>


[[Category:Guide]]
[[Category:Guide]]
Retrieved from "https://wiki.nixos.org/wiki/ZFS"