Merge pull request #70601 from Mic92/zfs-trim

nixos/zfs: only enable trim if zfs is enabled

nixos/doc/manual/release-notes/rl-2003.xml

@@ -36,6 +36,19 @@
      quirk in the boot menu.
     </para>
    </listitem>
+   <listitem>
+     <para>
+       By default zfs pools will now be trimmed on a weekly basis.
+       Trimming is only done on supported devices (i.e. NVME or SSDs)
+       and should improve throughput and lifetime of these devices.
+       It is controlled by the <varname>services.zfs.trim.enable</varname> varname.
+       The zfs scrub service (<varname>services.zfs.autoScrub.enable</varname>)
+       and the zfs autosnapshot service (<varname>services.zfs.autoSnapshot.enable</varname>)
+       are now only enabled if zfs is set in <varname>config.boot.initrd.supportedFilesystems</varname> or
+       <varname>config.boot.supportedFilesystems</varname>. These lists will automatically contain
+       zfs as soon as any zfs mountpoint is configured in <varname>fileSystems</varname>.
+     </para>
+   </listitem>
   </itemizedlist>
  </section>
 

nixos/modules/tasks/filesystems/zfs.nix

@@ -16,9 +16,7 @@ let
   inInitrd = any (fs: fs == "zfs") config.boot.initrd.supportedFilesystems;
   inSystem = any (fs: fs == "zfs") config.boot.supportedFilesystems;
 
-  enableAutoSnapshots = cfgSnapshots.enable;
+  enableZfs = inInitrd || inSystem;
-  enableAutoScrub = cfgScrub.enable;
-  enableZfs = inInitrd || inSystem || enableAutoSnapshots || enableAutoScrub;
 
   kernel = config.boot.kernelPackages;
 
@@ -395,7 +393,7 @@ in
 
       system.fsPackages = [ packages.zfsUser ]; # XXX: needed? zfs doesn't have (need) a fsck
       environment.systemPackages = [ packages.zfsUser ]
-        ++ optional enableAutoSnapshots autosnapPkg; # so the user can run the command to see flags
+        ++ optional cfgSnapshots.enable autosnapPkg; # so the user can run the command to see flags
 
       services.udev.packages = [ packages.zfsUser ]; # to hook zvol naming, etc.
       systemd.packages = [ packages.zfsUser ];
@@ -487,7 +485,7 @@ in
       systemd.targets.zfs.wantedBy = [ "multi-user.target" ];
     })
 
-    (mkIf enableAutoSnapshots {
+    (mkIf (enableZfs && cfgSnapshots.enable) {
       systemd.services = let
                            descr = name: if name == "frequent" then "15 mins"
                                     else if name == "hourly" then "hour"
@@ -525,7 +523,7 @@ in
                             }) snapshotNames);
     })
 
-    (mkIf enableAutoScrub {
+    (mkIf (enableZfs && cfgScrub.enable) {
       systemd.services.zfs-scrub = {
         description = "ZFS pools scrubbing";
         after = [ "zfs-import.target" ];
@@ -552,15 +550,13 @@ in
       };
     })
 
-    (mkIf cfgTrim.enable {
+    (mkIf (enableZfs && cfgTrim.enable) {
       systemd.services.zpool-trim = {
         description = "ZFS pools trim";
         after = [ "zfs-import.target" ];
         path = [ packages.zfsUser ];
         startAt = cfgTrim.interval;
-        script = ''
+        serviceConfig.ExecStart = "${pkgs.runtimeShell} -c 'zpool list -H -o name | xargs --no-run-if-empty -n1 zpool trim'";
-          zpool list -H -o name | xargs -n1 zpool trim
-        '';
       };
     })
   ];