LVM: Difference between revisions

Line 11:

=== Create an LV ===

Below are shell commands to setup a PV, a VG and an LV from scratch. LVM comes enabled by default on NixOS.<syntaxhighlight lang="shell">

<~~syntaxHighlight~~ lang=~~bash~~>

# format the partion into a physical volume (check with pvdisplay)

# ~~formats~~ the partion into a physical volume (check with pvdisplay)

pvcreate /dev/sda2

# ~~creates~~ a new volume group named pool (check with vgdisplay)

# create a new volume group named pool (check with vgdisplay)

vgcreate pool /dev/sda2

# ~~creates~~ a new logical volume named "home" with the size of 10GB (check with lvdisplay)

# create a new logical volume named "home" with the size of 10GB (check with lvdisplay)

# makes /dev/pool/home available

lvcreate --size 10G --name home pool

# finally, create a filesystem inside the logical volume

mkfs.ext4 /dev/pool/home

</~~syntaxHighlight~~>

</syntaxhighlight>

=== Use the LV ===

~~in your <code>configuration~~.~~nix</code>:~~

Mount the filesystem on the logical volume by adding an entry to the {{Nixos:option|fileSystems}} NixOS option.

{{File|3=fileSystems."/home" = {

~~<syntaxHighlight lang~~=~~nix>~~

fileSystems."/home" = {

device = "/dev/pool/home";

fsType = "ext4";

};

};|name=/etc/nixos/configuration.nix|lang=nix}}

</~~syntaxHighlight>~~

== Booting with special LVM Modes ==

LVM provides a number of special features such as creating snapshots, RAID for single LVs and much more. If you want to use these devices on bootup, the associated <code>dm-*</code> kernel module must be provided in the initrd (see for example {{Issue|33646}}). ~~This~~ is a non-exhaustive list of features and the corresponding kernel module and other options to put into your ~~<code>~~configuration~~.nix</code>~~:

LVM provides a number of special features such as creating snapshots, RAID for single LVs and much more. If you want to use these devices on bootup, the associated <code>dm-*</code> kernel module must be provided in the initrd (see for example Nixpkgs issue {{Issue|33646}}). Here is a non-exhaustive list of features and the corresponding kernel module and other options to put into your NixOS configuration:

~~<syntaxHighlight lang~~=~~nix>~~

boot.initrd.kernelModules = [

{{File|3=boot.initrd.kernelModules = [

"dm-snapshot" # when you are using snapshots

"dm-raid" # e.g. when you are configuring raid1 via: `lvconvert -m1 /dev/pool/home`

Line 42:

Line 39:

];

services.lvm.boot.thin.enable = true; # when using thin provisioning or caching

services.lvm.boot.thin.enable = true; # when using thin provisioning or caching|name=/etc/nixos/configuration.nix|lang=nix}}

</~~syntaxHighlight>~~

== Automated Partitioning ==

@@ Line 11: / Line 11: @@
 === Create an LV ===
+Below are shell commands to setup a PV, a VG and an LV from scratch. LVM comes enabled by default on NixOS.<syntaxhighlight lang="shell">
-<syntaxHighlight lang=bash>
+# format the partion into a physical volume (check with pvdisplay)
-# formats the partion into a physical volume (check with pvdisplay)
 pvcreate /dev/sda2
-# creates a new volume group named pool (check with vgdisplay)
+# create a new volume group named pool (check with vgdisplay)
 vgcreate pool /dev/sda2
-# creates a new logical volume named "home" with the size of 10GB (check with lvdisplay)
+# create a new logical volume named "home" with the size of 10GB (check with lvdisplay)
 # makes /dev/pool/home available
 lvcreate --size 10G --name home pool
+# finally, create a filesystem inside the logical volume
 mkfs.ext4 /dev/pool/home
-</syntaxHighlight>
+</syntaxhighlight>
 === Use the LV ===
-in your <code>configuration.nix</code>:
+Mount the filesystem on the logical volume by adding an entry to the {{Nixos:option|fileSystems}} NixOS option.
+{{File|3=fileSystems."/home" = {
-<syntaxHighlight lang=nix>
-fileSystems."/home" = {
    device = "/dev/pool/home";
    fsType = "ext4";
-};
+};|name=/etc/nixos/configuration.nix|lang=nix}}
-</syntaxHighlight>
 == Booting with special LVM Modes ==
-LVM provides a number of special features such as creating snapshots, RAID for single LVs and much more. If you want to use these devices on bootup, the associated <code>dm-*</code> kernel module must be provided in the initrd (see for example {{Issue|33646}}). This is a non-exhaustive list of features and the corresponding kernel module and other options to put into your <code>configuration.nix</code>:
+LVM provides a number of special features such as creating snapshots, RAID for single LVs and much more. If you want to use these devices on bootup, the associated <code>dm-*</code> kernel module must be provided in the initrd (see for example Nixpkgs issue {{Issue|33646}}). Here is a non-exhaustive list of features and the corresponding kernel module and other options to put into your NixOS configuration:
-<syntaxHighlight lang=nix>
-boot.initrd.kernelModules = [
+{{File|3=boot.initrd.kernelModules = [
    "dm-snapshot" # when you are using snapshots
    "dm-raid" # e.g. when you are configuring raid1 via: `lvconvert -m1 /dev/pool/home`
@@ Line 42: / Line 39: @@
 ];
-services.lvm.boot.thin.enable = true; # when using thin provisioning or caching
+services.lvm.boot.thin.enable = true; # when using thin provisioning or caching|name=/etc/nixos/configuration.nix|lang=nix}}
-</syntaxHighlight>
 == Automated Partitioning ==