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


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 make sure that swapfiles on ZFS are not used, set <code>boot.zfs.allowHibernation = true</code>.
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>.


==== Zpool not found ====
==== Zpool not found ====
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== Guides ==
== Guides ==


=== OpenZFS Documentation for installing ===
=== Root on ZFS with disko ===
{{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.}}


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


It is about:
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.
* [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].
 
It is not about:
* Giving understandable, easy to follow instructions which are close to the standard installation guide
* Integrating ZFS into your existing config


=== Simple NixOS ZFS on root installation ===
=== Simple NixOS ZFS on root installation ===
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== Take snapshots automatically ==
== Take snapshots automatically ==


See {{nixos:option|services.sanoid}} 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 ==
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</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:
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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]
=== 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:
<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;
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     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";
       };
       };
     };
     };
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{
{
   environment.etc.aliases.text = ''
   environment.etc.aliases.text = ''
     root: you@example.com
     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>
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</syntaxhighlight>
</syntaxhighlight>


=== 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.
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"