ZFS: Difference between revisions

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Disable the mount service with <code>systemd.services.zfs-mount.enable = false;</code> or remove the <code>fileSystems</code> entries in hardware-configuration.nix. Otherwise, use legacy mountpoints (created with e.g. <code>zfs create -o mountpoint=legacy</code>). Mountpoints must be specified with <code>fileSystems."/mount/point" = {};</code> or with <code>nixos-generate-config</code>.

==== Nix builds and ZFS properties like normalization or utf8only ====

These options are often suggested in guides to setting up ZFS. <code>normalization</code> makes filenames compare the same in cases where there exists more than one UTF8 bytestring that represents the same characters. <code>utf8only</code> prevents the creation of files with non-UTF8 filenames, e.g. filenames using a Latin1 character set. These are non-POSIX and will make the tests for certain packages fail, which may interfere with builds. After nix 2.30, builds no longer happen in /tmp by default, instead they happen in <code>/nix/var/nix/builds</code>. On any system where you plan to run nix builds, you should ensure that this filesystem is POSIX-compliant. Either mounting a tmpfs in that directory (if you have lots of RAM + swap) or creating a zfs dataset there which does not have these or other non-POSIX settings like <code>noatime</code>, <code>snapdir=visible</code>, <code>acltype=nfsv4</code>, or <code>caseinsensitivity=insensitive</code>. Many of these cannot be changed after dataset creation so if this is your root filesystem, you will need to restore from a backup in order to recreate them.

== Guides ==

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</syntaxhighlight>

You can confirm whether any specified configuration/tuning got applied via commands like <code>~~arc_summary~~</code> and <code>~~arcstat~~ -a -s " "</code>.

You can confirm whether any specified configuration/tuning got applied via commands like <code>zarcsummary</code> and <code>zarcstat -a -s " "</code>.

== Automatic scrubbing ==

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=== Unlock encrypted ZFS via SSH on boot ===

{{~~note~~|As of 22.05, rebuilding your config with the below directions may result in a situation where, if you want to revert the changes, you may need to do some pretty hairy nix-store manipulation to be able to successfully rebuild, see https://github.com/NixOS/nixpkgs/issues/101462#issuecomment-1172926129}}

{{merge|Remote_disk_unlocking}}In case you want unlock a machine remotely (after an update), having an ssh service in initrd for the password prompt is handy:

In case you want unlock a machine remotely (after an update), having an ssh service in initrd for the password prompt is handy:

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== Take snapshots automatically ==

See {{nixos:option|services.sanoid}} section in <code>man configuration.nix</code>.

See {{nixos:option|services.zfs.autoSnapshot}} or {{nixos:option|services.sanoid}} section in <code>man configuration.nix</code>.

== NFS share ==

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{

services.zfs.zed. = {

services.zfs.zed = {

enableMail = true;

settings = {

@@ Line 62: / Line 62: @@
 Disable the mount service with <code>systemd.services.zfs-mount.enable = false;</code> or remove the <code>fileSystems</code> entries in hardware-configuration.nix. Otherwise, use legacy mountpoints (created with e.g. <code>zfs create -o mountpoint=legacy</code>). Mountpoints must be specified with <code>fileSystems."/mount/point" = {};</code> or with <code>nixos-generate-config</code>.
+==== Nix builds and ZFS properties like normalization or utf8only ====
+These options are often suggested in guides to setting up ZFS. <code>normalization</code> makes filenames compare the same in cases where there exists more than one UTF8 bytestring that represents the same characters. <code>utf8only</code> prevents the creation of files with non-UTF8 filenames, e.g. filenames using a Latin1 character set. These are non-POSIX and will make the tests for certain packages fail, which may interfere with builds. After nix 2.30, builds no longer happen in /tmp by default, instead they happen in <code>/nix/var/nix/builds</code>. On any system where you plan to run nix builds, you should ensure that this filesystem is POSIX-compliant. Either mounting a tmpfs in that directory (if you have lots of RAM + swap) or creating a zfs dataset there which does not have these or other non-POSIX settings like <code>noatime</code>, <code>snapdir=visible</code>, <code>acltype=nfsv4</code>, or <code>caseinsensitivity=insensitive</code>. Many of these cannot be changed after dataset creation so if this is your root filesystem, you will need to restore from a backup in order to recreate them.
 == Guides ==
@@ Line 323: / Line 326: @@
 </syntaxhighlight>
-You can confirm whether any specified configuration/tuning got applied via commands like <code>arc_summary</code> and <code>arcstat -a -s " "</code>.
+You can confirm whether any specified configuration/tuning got applied via commands like <code>zarcsummary</code> and <code>zarcstat -a -s " "</code>.
 == Automatic scrubbing ==
@@ Line 336: / Line 339: @@
 === Unlock encrypted ZFS via SSH on boot ===
-{{note|As of 22.05, rebuilding your config with the below directions may result in a situation where, if you want to revert the changes, you may need to do some pretty hairy nix-store manipulation to be able to successfully rebuild, see https://github.com/NixOS/nixpkgs/issues/101462#issuecomment-1172926129}}
+{{merge|Remote_disk_unlocking}}In case you want unlock a machine remotely (after an update), having an ssh service in initrd for the password prompt is handy:
-In case you want unlock a machine remotely (after an update), having an ssh service in initrd for the password prompt is handy:
 <syntaxhighlight lang="nix">
@@ Line 419: / Line 420: @@
 == Take snapshots automatically ==
-See {{nixos:option|services.sanoid}} section in <code>man configuration.nix</code>.
+See {{nixos:option|services.zfs.autoSnapshot}} or {{nixos:option|services.sanoid}} section in <code>man configuration.nix</code>.
 == NFS share ==
@@ Line 496: / Line 497: @@
 <syntaxhighlight lang="nix">
 {
-   services.zfs.zed. = {
+   services.zfs.zed = {
      enableMail = true;
      settings = {