b0a51de6c1
Otherwise, in certain cases, snapshots of infrequently-modified filesystems can be kept for a much longer time than the user would normally expect, and cause a large amount of extra disk space to be consumed. Also added flag to snapshot filesystems in parallel by default. I've also added a configuration option for zfs-auto-snapshot flags, so that the user can override them. For example, the user may want to append --utc to the list of default options, so that the snapshot names don't cause name conflicts or apparent time reversals due to daylight savings or timezone changes.
366 lines
12 KiB
Nix
366 lines
12 KiB
Nix
{ config, lib, pkgs, utils, ... }:
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#
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# todo:
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# - crontab for scrubs, etc
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# - zfs tunables
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with utils;
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with lib;
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let
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cfgSpl = config.boot.spl;
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cfgZfs = config.boot.zfs;
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cfgSnapshots = config.services.zfs.autoSnapshot;
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cfgSnapFlags = cfgSnapshots.flags;
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inInitrd = any (fs: fs == "zfs") config.boot.initrd.supportedFilesystems;
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inSystem = any (fs: fs == "zfs") config.boot.supportedFilesystems;
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enableAutoSnapshots = cfgSnapshots.enable;
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enableZfs = inInitrd || inSystem || enableAutoSnapshots;
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kernel = config.boot.kernelPackages;
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splKernelPkg = if cfgZfs.useGit then kernel.spl_git else kernel.spl;
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zfsKernelPkg = if cfgZfs.useGit then kernel.zfs_git else kernel.zfs;
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zfsUserPkg = if cfgZfs.useGit then pkgs.zfs_git else pkgs.zfs;
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autosnapPkg = pkgs.zfstools.override {
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zfs = zfsUserPkg;
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};
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zfsAutoSnap = "${autosnapPkg}/bin/zfs-auto-snapshot";
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datasetToPool = x: elemAt (splitString "/" x) 0;
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fsToPool = fs: datasetToPool fs.device;
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zfsFilesystems = filter (x: x.fsType == "zfs") (attrValues config.fileSystems);
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isRoot = fs: fs.neededForBoot || elem fs.mountPoint [ "/" "/nix" "/nix/store" "/var" "/var/log" "/var/lib" "/etc" ];
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allPools = unique ((map fsToPool zfsFilesystems) ++ cfgZfs.extraPools);
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rootPools = unique (map fsToPool (filter isRoot zfsFilesystems));
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dataPools = unique (filter (pool: !(elem pool rootPools)) allPools);
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in
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{
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###### interface
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options = {
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boot.zfs = {
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useGit = mkOption {
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type = types.bool;
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default = false;
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example = true;
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description = ''
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Use the git version of the SPL and ZFS packages.
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Note that these are unreleased versions, with less testing, and therefore
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may be more unstable.
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'';
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};
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extraPools = mkOption {
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type = types.listOf types.str;
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default = [];
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example = [ "tank" "data" ];
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description = ''
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Name or GUID of extra ZFS pools that you wish to import during boot.
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Usually this is not necessary. Instead, you should set the mountpoint property
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of ZFS filesystems to <literal>legacy</literal> and add the ZFS filesystems to
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NixOS's <option>fileSystems</option> option, which makes NixOS automatically
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import the associated pool.
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However, in some cases (e.g. if you have many filesystems) it may be preferable
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to exclusively use ZFS commands to manage filesystems. If so, since NixOS/systemd
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will not be managing those filesystems, you will need to specify the ZFS pool here
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so that NixOS automatically imports it on every boot.
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'';
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};
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forceImportRoot = mkOption {
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type = types.bool;
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default = true;
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example = false;
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description = ''
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Forcibly import the ZFS root pool(s) during early boot.
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This is enabled by default for backwards compatibility purposes, but it is highly
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recommended to disable this option, as it bypasses some of the safeguards ZFS uses
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to protect your ZFS pools.
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If you set this option to <literal>false</literal> and NixOS subsequently fails to
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boot because it cannot import the root pool, you should boot with the
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<literal>zfs_force=1</literal> option as a kernel parameter (e.g. by manually
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editing the kernel params in grub during boot). You should only need to do this
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once.
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'';
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};
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forceImportAll = mkOption {
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type = types.bool;
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default = true;
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example = false;
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description = ''
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Forcibly import all ZFS pool(s).
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This is enabled by default for backwards compatibility purposes, but it is highly
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recommended to disable this option, as it bypasses some of the safeguards ZFS uses
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to protect your ZFS pools.
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If you set this option to <literal>false</literal> and NixOS subsequently fails to
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import your non-root ZFS pool(s), you should manually import each pool with
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"zpool import -f <pool-name>", and then reboot. You should only need to do
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this once.
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'';
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};
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};
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services.zfs.autoSnapshot = {
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enable = mkOption {
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default = false;
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type = types.bool;
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description = ''
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Enable the (OpenSolaris-compatible) ZFS auto-snapshotting service.
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Note that you must set the <literal>com.sun:auto-snapshot</literal>
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property to <literal>true</literal> on all datasets which you wish
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to auto-snapshot.
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You can override a child dataset to use, or not use auto-snapshotting
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by setting its flag with the given interval:
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<literal>zfs set com.sun:auto-snapshot:weekly=false DATASET</literal>
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'';
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};
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flags = mkOption {
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default = "-k -p";
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example = "-k -p --utc";
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type = types.str;
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description = ''
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Flags to pass to the zfs-auto-snapshot command.
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Run <literal>zfs-auto-snapshot</literal> (without any arguments) to
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see available flags.
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If it's not too inconvenient for snapshots to have timestamps in UTC,
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it is suggested that you append <literal>--utc</literal> to the list
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of default options (see example).
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Otherwise, snapshot names can cause name conflicts or apparent time
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reversals due to daylight savings, timezone or other date/time changes.
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'';
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};
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frequent = mkOption {
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default = 4;
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type = types.int;
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description = ''
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Number of frequent (15-minute) auto-snapshots that you wish to keep.
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'';
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};
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hourly = mkOption {
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default = 24;
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type = types.int;
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description = ''
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Number of hourly auto-snapshots that you wish to keep.
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'';
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};
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daily = mkOption {
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default = 7;
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type = types.int;
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description = ''
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Number of daily auto-snapshots that you wish to keep.
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'';
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};
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weekly = mkOption {
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default = 4;
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type = types.int;
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description = ''
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Number of weekly auto-snapshots that you wish to keep.
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'';
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};
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monthly = mkOption {
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default = 12;
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type = types.int;
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description = ''
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Number of monthly auto-snapshots that you wish to keep.
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'';
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};
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};
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};
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###### implementation
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config = mkMerge [
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(mkIf enableZfs {
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assertions = [
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{
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assertion = config.networking.hostId != null;
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message = "ZFS requires config.networking.hostId to be set";
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}
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{
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assertion = !cfgZfs.forceImportAll || cfgZfs.forceImportRoot;
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message = "If you enable boot.zfs.forceImportAll, you must also enable boot.zfs.forceImportRoot";
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}
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];
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boot = {
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kernelModules = [ "spl" "zfs" ] ;
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extraModulePackages = [ splKernelPkg zfsKernelPkg ];
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};
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boot.initrd = mkIf inInitrd {
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kernelModules = [ "spl" "zfs" ];
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extraUtilsCommands =
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''
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cp -v ${zfsUserPkg}/sbin/zfs $out/bin
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cp -v ${zfsUserPkg}/sbin/zdb $out/bin
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cp -v ${zfsUserPkg}/sbin/zpool $out/bin
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cp -pdv ${zfsUserPkg}/lib/lib*.so* $out/lib
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cp -pdv ${pkgs.zlib}/lib/lib*.so* $out/lib
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'';
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postDeviceCommands = concatStringsSep "\n" ([''
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ZFS_FORCE="${optionalString cfgZfs.forceImportRoot "-f"}"
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for o in $(cat /proc/cmdline); do
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case $o in
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zfs_force|zfs_force=1)
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ZFS_FORCE="-f"
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;;
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esac
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done
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''] ++ (map (pool: ''
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echo "importing root ZFS pool \"${pool}\"..."
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zpool import -N $ZFS_FORCE "${pool}"
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'') rootPools));
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};
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boot.loader.grub = mkIf inInitrd {
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zfsSupport = true;
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};
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environment.etc."zfs/zed.d".source = "${zfsUserPkg}/etc/zfs/zed.d/*";
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system.fsPackages = [ zfsUserPkg ]; # XXX: needed? zfs doesn't have (need) a fsck
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environment.systemPackages = [ zfsUserPkg ]
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++ optional enableAutoSnapshots autosnapPkg; # so the user can run the command to see flags
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services.udev.packages = [ zfsUserPkg ]; # to hook zvol naming, etc.
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systemd.packages = [ zfsUserPkg ];
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systemd.services = let
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getPoolFilesystems = pool:
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filter (x: x.fsType == "zfs" && (fsToPool x) == pool) (attrValues config.fileSystems);
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getPoolMounts = pool:
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let
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mountPoint = fs: escapeSystemdPath fs.mountPoint;
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in
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map (x: "${mountPoint x}.mount") (getPoolFilesystems pool);
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createImportService = pool:
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nameValuePair "zfs-import-${pool}" {
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description = "Import ZFS pool \"${pool}\"";
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requires = [ "systemd-udev-settle.service" ];
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after = [ "systemd-udev-settle.service" "systemd-modules-load.service" ];
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wantedBy = (getPoolMounts pool) ++ [ "local-fs.target" ];
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before = (getPoolMounts pool) ++ [ "local-fs.target" ];
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unitConfig = {
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DefaultDependencies = "no";
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};
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serviceConfig = {
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Type = "oneshot";
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RemainAfterExit = true;
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};
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script = ''
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zpool_cmd="${zfsUserPkg}/sbin/zpool"
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("$zpool_cmd" list "${pool}" >/dev/null) || "$zpool_cmd" import -N ${optionalString cfgZfs.forceImportAll "-f"} "${pool}"
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'';
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};
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in listToAttrs (map createImportService dataPools) // {
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"zfs-mount" = { after = [ "systemd-modules-load.service" ]; };
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"zfs-share" = { after = [ "systemd-modules-load.service" ]; };
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"zed" = { after = [ "systemd-modules-load.service" ]; };
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};
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systemd.targets."zfs-import" =
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let
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services = map (pool: "zfs-import-${pool}.service") dataPools;
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in
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{
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requires = services;
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after = services;
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};
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systemd.targets."zfs".wantedBy = [ "multi-user.target" ];
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})
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(mkIf enableAutoSnapshots {
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systemd.services."zfs-snapshot-frequent" = {
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description = "ZFS auto-snapshotting every 15 mins";
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after = [ "zfs-import.target" ];
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serviceConfig = {
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Type = "oneshot";
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ExecStart = "${zfsAutoSnap} ${cfgSnapFlags} frequent ${toString cfgSnapshots.frequent}";
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};
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restartIfChanged = false;
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startAt = "*:15,30,45";
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};
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systemd.services."zfs-snapshot-hourly" = {
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description = "ZFS auto-snapshotting every hour";
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after = [ "zfs-import.target" ];
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serviceConfig = {
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Type = "oneshot";
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ExecStart = "${zfsAutoSnap} ${cfgSnapFlags} hourly ${toString cfgSnapshots.hourly}";
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};
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restartIfChanged = false;
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startAt = "hourly";
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};
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systemd.services."zfs-snapshot-daily" = {
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description = "ZFS auto-snapshotting every day";
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after = [ "zfs-import.target" ];
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serviceConfig = {
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Type = "oneshot";
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ExecStart = "${zfsAutoSnap} ${cfgSnapFlags} daily ${toString cfgSnapshots.daily}";
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};
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restartIfChanged = false;
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startAt = "daily";
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};
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systemd.services."zfs-snapshot-weekly" = {
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description = "ZFS auto-snapshotting every week";
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after = [ "zfs-import.target" ];
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serviceConfig = {
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Type = "oneshot";
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ExecStart = "${zfsAutoSnap} ${cfgSnapFlags} weekly ${toString cfgSnapshots.weekly}";
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};
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restartIfChanged = false;
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startAt = "weekly";
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};
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systemd.services."zfs-snapshot-monthly" = {
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description = "ZFS auto-snapshotting every month";
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after = [ "zfs-import.target" ];
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serviceConfig = {
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Type = "oneshot";
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ExecStart = "${zfsAutoSnap} ${cfgSnapFlags} monthly ${toString cfgSnapshots.monthly}";
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};
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restartIfChanged = false;
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startAt = "monthly";
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};
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})
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];
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}
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