nixpkgs/nixos/modules/tasks/filesystems/zfs.nix
2016-04-15 17:25:32 +01:00

349 lines
11 KiB
Nix

{ config, lib, pkgs, utils, ... }:
#
# todo:
# - crontab for scrubs, etc
# - zfs tunables
with utils;
with lib;
let
cfgSpl = config.boot.spl;
cfgZfs = config.boot.zfs;
cfgSnapshots = config.services.zfs.autoSnapshot;
inInitrd = any (fs: fs == "zfs") config.boot.initrd.supportedFilesystems;
inSystem = any (fs: fs == "zfs") config.boot.supportedFilesystems;
enableAutoSnapshots = cfgSnapshots.enable;
enableZfs = inInitrd || inSystem || enableAutoSnapshots;
kernel = config.boot.kernelPackages;
splKernelPkg = kernel.spl;
zfsKernelPkg = kernel.zfs;
zfsUserPkg = pkgs.zfs;
autosnapPkg = pkgs.zfstools.override {
zfs = zfsUserPkg;
};
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
{
###### interface
options = {
boot.zfs = {
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.
'';
};
devNodes = mkOption {
type = types.path;
default = "/dev/disk/by-id";
example = "/dev/disk/by-id";
description = ''
Name of directory from which to import ZFS devices.
This should be a path under /dev containing stable names for all devices needed, as
import may fail if device nodes are renamed concurrently with a device failing.
'';
};
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 &lt;pool-name&gt;", and then reboot. You should only need to do
this once.
'';
};
};
services.zfs.autoSnapshot = {
enable = mkOption {
default = false;
type = types.bool;
description = ''
Enable the (OpenSolaris-compatible) ZFS auto-snapshotting service.
Note that you must set the <literal>com.sun:auto-snapshot</literal>
property to <literal>true</literal> on all datasets which you wish
to auto-snapshot.
You can override a child dataset to use, or not use auto-snapshotting
by setting its flag with the given interval:
<literal>zfs set com.sun:auto-snapshot:weekly=false DATASET</literal>
'';
};
frequent = mkOption {
default = 4;
type = types.int;
description = ''
Number of frequent (15-minute) auto-snapshots that you wish to keep.
'';
};
hourly = mkOption {
default = 24;
type = types.int;
description = ''
Number of hourly auto-snapshots that you wish to keep.
'';
};
daily = mkOption {
default = 7;
type = types.int;
description = ''
Number of daily auto-snapshots that you wish to keep.
'';
};
weekly = mkOption {
default = 4;
type = types.int;
description = ''
Number of weekly auto-snapshots that you wish to keep.
'';
};
monthly = mkOption {
default = 12;
type = types.int;
description = ''
Number of monthly auto-snapshots that you wish to keep.
'';
};
};
};
###### implementation
config = mkMerge [
(mkIf enableZfs {
assertions = [
{
assertion = config.networking.hostId != null;
message = "ZFS requires config.networking.hostId to be set";
}
{
assertion = !cfgZfs.forceImportAll || cfgZfs.forceImportRoot;
message = "If you enable boot.zfs.forceImportAll, you must also enable boot.zfs.forceImportRoot";
}
];
boot = {
kernelModules = [ "spl" "zfs" ] ;
extraModulePackages = [ splKernelPkg zfsKernelPkg ];
};
boot.initrd = mkIf inInitrd {
kernelModules = [ "spl" "zfs" ];
extraUtilsCommands =
''
copy_bin_and_libs ${zfsUserPkg}/sbin/zfs
copy_bin_and_libs ${zfsUserPkg}/sbin/zdb
copy_bin_and_libs ${zfsUserPkg}/sbin/zpool
'';
extraUtilsCommandsTest = mkIf inInitrd
''
$out/bin/zfs --help >/dev/null 2>&1
$out/bin/zpool --help >/dev/null 2>&1
'';
postDeviceCommands = concatStringsSep "\n" ([''
ZFS_FORCE="${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 -d ${cfgZfs.devNodes} -N $ZFS_FORCE "${pool}"
'') rootPools));
};
boot.loader.grub = mkIf inInitrd {
zfsSupport = true;
};
environment.etc."zfs/zed.d".source = "${zfsUserPkg}/etc/zfs/zed.d/*";
system.fsPackages = [ zfsUserPkg ]; # XXX: needed? zfs doesn't have (need) a fsck
environment.systemPackages = [ zfsUserPkg ];
services.udev.packages = [ zfsUserPkg ]; # to hook zvol naming, etc.
systemd.packages = [ zfsUserPkg ];
systemd.services = let
getPoolFilesystems = pool:
filter (x: x.fsType == "zfs" && (fsToPool x) == pool) (attrValues config.fileSystems);
getPoolMounts = pool:
let
mountPoint = fs: escapeSystemdPath fs.mountPoint;
in
map (x: "${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="${zfsUserPkg}/sbin/zpool"
("$zpool_cmd" list "${pool}" >/dev/null) || "$zpool_cmd" import -d ${cfgZfs.devNodes} -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-${pool}.service") dataPools;
in
{
requires = services;
after = services;
};
systemd.targets."zfs".wantedBy = [ "multi-user.target" ];
})
(mkIf enableAutoSnapshots {
systemd.services."zfs-snapshot-frequent" = {
description = "ZFS auto-snapshotting every 15 mins";
after = [ "zfs-import.target" ];
serviceConfig = {
Type = "oneshot";
ExecStart = "${zfsAutoSnap} frequent ${toString cfgSnapshots.frequent}";
};
restartIfChanged = false;
startAt = "*:15,30,45";
};
systemd.services."zfs-snapshot-hourly" = {
description = "ZFS auto-snapshotting every hour";
after = [ "zfs-import.target" ];
serviceConfig = {
Type = "oneshot";
ExecStart = "${zfsAutoSnap} hourly ${toString cfgSnapshots.hourly}";
};
restartIfChanged = false;
startAt = "hourly";
};
systemd.services."zfs-snapshot-daily" = {
description = "ZFS auto-snapshotting every day";
after = [ "zfs-import.target" ];
serviceConfig = {
Type = "oneshot";
ExecStart = "${zfsAutoSnap} daily ${toString cfgSnapshots.daily}";
};
restartIfChanged = false;
startAt = "daily";
};
systemd.services."zfs-snapshot-weekly" = {
description = "ZFS auto-snapshotting every week";
after = [ "zfs-import.target" ];
serviceConfig = {
Type = "oneshot";
ExecStart = "${zfsAutoSnap} weekly ${toString cfgSnapshots.weekly}";
};
restartIfChanged = false;
startAt = "weekly";
};
systemd.services."zfs-snapshot-monthly" = {
description = "ZFS auto-snapshotting every month";
after = [ "zfs-import.target" ];
serviceConfig = {
Type = "oneshot";
ExecStart = "${zfsAutoSnap} monthly ${toString cfgSnapshots.monthly}";
};
restartIfChanged = false;
startAt = "monthly";
};
})
];
}