From 35987b0c2990fd0c096c0e955eafa1984196d922 Mon Sep 17 00:00:00 2001
From: Christoph Cullmann <christoph@cullmann.io>
Date: Thu, 3 Oct 2024 11:17:39 +0200
Subject: [PATCH] setup ZFS services again

---
 share/common.nix | 53 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/share/common.nix b/share/common.nix
index 3538340..feae129 100644
--- a/share/common.nix
+++ b/share/common.nix
@@ -25,16 +25,37 @@ in
   # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
   system.stateVersion = "23.05"; # Did you read the comment?
 
-  # use the latest kernel with ZFS support and enable that file system
-  boot.kernelPackages = config.boot.zfs.package.latestCompatibleLinuxPackages;
+  # enable ZFS
   boot.supportedFilesystems = [ "zfs" ];
 
   # my kernel parameters
   boot.kernelParams = [
+    # no hibernate for ZFS systems
+    "nohibernate"
+
     # don't check for split locks, for KVM and Co.
     "split_lock_detect=off"
   ];
 
+  # tweak ZFS
+  boot.extraModprobeConfig = ''
+    options zfs zfs_arc_meta_limit_percent=75
+    options zfs zfs_arc_min=134217728
+    options zfs zfs_arc_max=4294967296
+    options zfs zfs_txg_timeout=30
+    options zfs zfs_vdev_scrub_min_active=1
+    options zfs zfs_vdev_scrub_max_active=1
+    options zfs zfs_vdev_sync_write_min_active=8
+    options zfs zfs_vdev_sync_write_max_active=32
+    options zfs zfs_vdev_sync_read_min_active=8
+    options zfs zfs_vdev_sync_read_max_active=32
+    options zfs zfs_vdev_async_read_min_active=8
+    options zfs zfs_vdev_async_read_max_active=32
+    options zfs zfs_vdev_async_write_min_active=8
+    options zfs zfs_vdev_async_write_max_active=32
+    options zfs zfs_vdev_def_queue_depth=128
+  '';
+
   # Use the systemd-boot EFI boot loader.
   boot.loader.systemd-boot.enable = true;
   boot.loader.efi.canTouchEfiVariables = true;
@@ -136,6 +157,15 @@ in
   # kill the tmp content on reboots, we mount that to /nix/persistent to avoid memory fill-up
   boot.tmp.cleanOnBoot = true;
 
+  # ensure our data is not rotting
+  services.zfs.autoScrub = {
+    enable = true;
+    interval = "weekly";
+  };
+
+  # trim the stuff, we use SSDs
+  services.zfs.trim.enable = true;
+
   # enable fast dbus
   services.dbus.implementation = "broker";
 
@@ -490,6 +520,25 @@ in
     mode = "0400";
   };
 
+  # send mails on ZFS events
+  services.zfs.zed = {
+    settings = {
+      ZED_DEBUG_LOG = "/tmp/zed.debug.log";
+      ZED_EMAIL_ADDR = [ "root" ];
+      ZED_EMAIL_PROG = "/run/wrappers/bin/sendmail";
+      ZED_EMAIL_OPTS = "@ADDRESS@";
+
+      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
+    enableMail = false;
+  };
+
   # use ZSH per default
   programs.zsh.enable = true;
   environment.shells = with pkgs; [ zsh ];