nixos/zfs: Improve the ZFS boot process (12e77fdc) · Commits · nix / nixpkgs

nixos/modules/tasks/filesystems/zfs.nix

+156 −24

Original line number	Diff line number	Diff line
		{ config, lib, pkgs, ... }:
		{ config, lib, pkgs, utils, ... }:
		#
		# todo:
		# - crontab for scrubs, etc
		# - zfs tunables
		# - /etc/zfs/zpool.cache handling


		with utils;
		with lib;

		let
		@@ -31,6 +30,20 @@ let

		zfsAutoSnap = "${autosnapPkg}/bin/zfs-auto-snapshot";

		datasetToPool = x: elemAt (splitString "/" x) 0;

		fsToPool = fs: datasetToPool fs.device;

		zfsFilesystems = filter (x: x.fsType == "zfs") (attrValues config.fileSystems);

		isRoot = fs: fs.neededForBoot \|\| elem fs.mountPoint [ "/" "/nix" "/nix/store" "/var" "/var/log" "/var/lib" "/etc" ];

		allPools = unique ((map fsToPool zfsFilesystems) ++ cfgZfs.extraPools);

		rootPools = unique (map fsToPool (filter isRoot zfsFilesystems));

		dataPools = unique (filter (pool: !(elem pool rootPools)) allPools);

		in

		{
		@@ -42,16 +55,17 @@ in
		default = "";
		example = "0xdeadbeef";
		description = ''
		ZFS uses a system's hostid to determine if a storage pool (zpool) is
		native to this system, and should thus be imported automatically.
		ZFS uses a system's hostid to determine if a storage pool (zpool) has been
		imported on this system, and can thus be used again without reimporting.
		Unfortunately, this hostid can change under linux from boot to boot (by
		changing network adapters, for instance). Specify a unique 32 bit hostid in
		hex here for zfs to prevent getting a random hostid between boots and having to
		manually import pools.
		manually and forcibly reimport pools.
		'';
		};

		boot.zfs.useGit = mkOption {
		boot.zfs = {
		useGit = mkOption {
		type = types.bool;
		default = false;
		example = true;
		@@ -62,6 +76,63 @@ in
		'';
		};

		extraPools = mkOption {
		type = types.listOf types.str;
		default = [];
		example = [ "tank" "data" ];
		description = ''
		Name or GUID of extra ZFS pools that you wish to import during boot.

		Usually this is not necessary. Instead, you should set the mountpoint property
		of ZFS filesystems to <literal>legacy</literal> and add the ZFS filesystems to
		NixOS's <option>fileSystems</option> option, which makes NixOS automatically
		import the associated pool.

		However, in some cases (e.g. if you have many filesystems) it may be preferable
		to exclusively use ZFS commands to manage filesystems. If so, since NixOS/systemd
		will not be managing those filesystems, you will need to specify the ZFS pool here
		so that NixOS automatically imports it on every boot.
		'';
		};

		forceImportRoot = mkOption {
		type = types.bool;
		default = true;
		example = false;
		description = ''
		Forcibly import the ZFS root pool(s) during early boot.

		This is enabled by default for backwards compatibility purposes, but it is highly
		recommended to disable this option, as it bypasses some of the safeguards ZFS uses
		to protect your ZFS pools.

		If you set this option to <literal>false</literal> and NixOS subsequently fails to
		boot because it cannot import the root pool, you should boot with the
		<literal>zfs_force=1</literal> option as a kernel parameter (e.g. by manually
		editing the kernel params in grub during boot). You should only need to do this
		once.
		'';
		};

		forceImportAll = mkOption {
		type = types.bool;
		default = true;
		example = false;
		description = ''
		Forcibly import all ZFS pool(s).

		This is enabled by default for backwards compatibility purposes, but it is highly
		recommended to disable this option, as it bypasses some of the safeguards ZFS uses
		to protect your ZFS pools.

		If you set this option to <literal>false</literal> and NixOS subsequently fails to
		import your non-root ZFS pool(s), you should manually import each pool with
		"zpool import -f <pool-name>", and then reboot. You should only need to do
		this once.
		'';
		};
		};

		services.zfs.autoSnapshot = {
		enable = mkOption {
		default = false;
		@@ -124,6 +195,13 @@ in

		config = mkMerge [
		(mkIf enableZfs {
		assertions = [
		{
		assertion = !cfgZfs.forceImportAll \|\| cfgZfs.forceImportRoot;
		message = "If you enable boot.zfs.forceImportAll, you must also enable boot.zfs.forceImportRoot";
		}
		];

		boot = {
		kernelModules = [ "spl" "zfs" ] ;
		extraModulePackages = [ splPkg zfsPkg ];
		@@ -142,10 +220,20 @@ in
		cp -pdv ${zfsPkg}/lib/lib.so $out/lib
		cp -pdv ${pkgs.zlib}/lib/lib.so $out/lib
		'';
		postDeviceCommands =
		''
		zpool import -f -a
		'';
		postDeviceCommands = concatStringsSep "\n" ([''
		ZFS_FORCE="${optionalString cfgZfs.forceImportRoot "-f"}"

		for o in $(cat /proc/cmdline); do
		case $o in
		zfs_force\|zfs_force=1)
		ZFS_FORCE="-f"
		;;
		esac
		done
		''] ++ (map (pool: ''
		echo "importing root ZFS pool \"${pool}\"..."
		zpool import -N $ZFS_FORCE "${pool}"
		'') rootPools));
		};

		boot.loader.grub = mkIf inInitrd {
		@@ -159,13 +247,57 @@ in
		services.udev.packages = [ zfsPkg ]; # to hook zvol naming, etc.
		systemd.packages = [ zfsPkg ];

		systemd.services = let
		getPoolFilesystems = pool:
		filter (x: x.fsType == "zfs" && (fsToPool x) == pool) (attrValues config.fileSystems);

		getPoolMounts = pool:
		let
		mountPoint = fs: escapeSystemdPath fs.mountPoint;
		in
		map (x: "${mountPoint x}.mount") (getPoolFilesystems pool);

		createImportService = pool:
		nameValuePair "zfs-import-${pool}" {
		description = "Import ZFS pool \"${pool}\"";
		requires = [ "systemd-udev-settle.service" ];
		after = [ "systemd-udev-settle.service" "systemd-modules-load.service" ];
		wantedBy = (getPoolMounts pool) ++ [ "local-fs.target" ];
		before = (getPoolMounts pool) ++ [ "local-fs.target" ];
		unitConfig = {
		DefaultDependencies = "no";
		};
		serviceConfig = {
		Type = "oneshot";
		RemainAfterExit = true;
		};
		script = ''
		zpool_cmd="${zfsPkg}/sbin/zpool"
		("$zpool_cmd" list "${pool}" >/dev/null) \|\| "$zpool_cmd" import -N ${optionalString cfgZfs.forceImportAll "-f"} "${pool}"
		'';
		};
		in listToAttrs (map createImportService dataPools) // {
		"zfs-mount" = { after = [ "systemd-modules-load.service" ]; };
		"zfs-share" = { after = [ "systemd-modules-load.service" ]; };
		"zed" = { after = [ "systemd-modules-load.service" ]; };
		};

		systemd.targets."zfs-import" =
		let
		services = map (pool: "zfs-import-${pool}.service") dataPools;
		in
		{
		requires = services;
		after = services;
		};

		systemd.targets."zfs".wantedBy = [ "multi-user.target" ];
		})

		(mkIf enableAutoSnapshots {
		systemd.services."zfs-snapshot-frequent" = {
		description = "ZFS auto-snapshotting every 15 mins";
		after = [ "zfs-import-scan.service" "zfs-import-cache.service" ];
		after = [ "zfs-import.target" ];
		serviceConfig = {
		Type = "oneshot";
		ExecStart = "${zfsAutoSnap} frequent ${toString cfgSnapshots.frequent}";
		@@ -176,7 +308,7 @@ in

		systemd.services."zfs-snapshot-hourly" = {
		description = "ZFS auto-snapshotting every hour";
		after = [ "zfs-import-scan.service" "zfs-import-cache.service" ];
		after = [ "zfs-import.target" ];
		serviceConfig = {
		Type = "oneshot";
		ExecStart = "${zfsAutoSnap} hourly ${toString cfgSnapshots.hourly}";
		@@ -187,7 +319,7 @@ in

		systemd.services."zfs-snapshot-daily" = {
		description = "ZFS auto-snapshotting every day";
		after = [ "zfs-import-scan.service" "zfs-import-cache.service" ];
		after = [ "zfs-import.target" ];
		serviceConfig = {
		Type = "oneshot";
		ExecStart = "${zfsAutoSnap} daily ${toString cfgSnapshots.daily}";
		@@ -198,7 +330,7 @@ in

		systemd.services."zfs-snapshot-weekly" = {
		description = "ZFS auto-snapshotting every week";
		after = [ "zfs-import-scan.service" "zfs-import-cache.service" ];
		after = [ "zfs-import.target" ];
		serviceConfig = {
		Type = "oneshot";
		ExecStart = "${zfsAutoSnap} weekly ${toString cfgSnapshots.weekly}";
		@@ -209,7 +341,7 @@ in

		systemd.services."zfs-snapshot-monthly" = {
		description = "ZFS auto-snapshotting every month";
		after = [ "zfs-import-scan.service" "zfs-import-cache.service" ];
		after = [ "zfs-import.target" ];
		serviceConfig = {
		Type = "oneshot";
		ExecStart = "${zfsAutoSnap} monthly ${toString cfgSnapshots.monthly}";

pkgs/os-specific/linux/zfs/default.nix

+12 −1

Original line number	Diff line number	Diff line
		@@ -50,6 +50,17 @@ stdenv.mkDerivation {

		enableParallelBuilding = true;

		# Remove provided services as they are buggy
		postInstall = ''
		rm $out/etc/systemd/system/zfs-import-*.service

		sed -i '/zfs-import-scan.service/d' $out/etc/systemd/system/*

		for i in $out/etc/systemd/system/*; do
		substituteInPlace $i --replace "zfs-import-cache.service" "zfs-import.target"
		done
		'';

		meta = {
		description = "ZFS Filesystem Linux Kernel module";
		longDescription = ''

pkgs/os-specific/linux/zfs/git.nix

+11 −0

Original line number	Diff line number	Diff line
		@@ -47,6 +47,17 @@ stdenv.mkDerivation {

		enableParallelBuilding = true;

		# Remove provided services as they are buggy
		postInstall = ''
		rm $out/etc/systemd/system/zfs-import-*.service

		sed -i '/zfs-import-scan.service/d' $out/etc/systemd/system/*

		for i in $out/etc/systemd/system/*; do
		substituteInPlace $i --replace "zfs-import-cache.service" "zfs-import.target"
		done
		'';

		meta = {
		description = "ZFS Filesystem Linux Kernel module";
		longDescription = ''

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