[[!summary chatGPT: This guide provides instructions for setting up a system using fdisk, mdadm, and LVM, with commands for creating RAID and configuring partitions. It also discusses the advantages of this setup and provides links to related resources.]]
[[!meta date="2012-04-09 22:50"]]
[[!tag linux nixos]]

[[!img media/nixos-lores.png alt="" style="float: right"]]

# what is this?

since i might require such an setup more often i post it here, so i don't forget it (see [1]).

**this guide works great for fdisk+mdadm+LVM** but it did not work for parted lately using ubuntu server. i don't know why, maybe because of the raid controller?

in case someone removes the commands from the nixos wiki, here are the commands again:

    mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1
    
    pvcreate /dev/md0
    vgcreate myvolgrp /dev/md0
    lvcreate -L 1G -n boot myvolgrp
    lvcreate -L 5G -n system myvolgrp
  
    mkfs.ext4 -n boot /dev/myvolgrp/boot
    mkfs.ext4 -n system /dev/myvolgrp/system
  
    mount -L system /mnt
    nixos-option --install
  
    cat /etc/nixos/configuration.nix
    ...
      { mountPoint = "/";
        label="system";
      }
      { mountPoint = "/boot";
        label="boot";
      }
    nixos-install


# advantages of this setup





	
  * **no special partition required** either something like /dev/sda1 or /dev/sdb1 **where /boot would be placed on**
  * LVM can be used for anything
  * still mdadm is below, which is a good thing




reminds me though that i should check if /etc/nixos/configuration.nix is capable of installing grub in several partitions already. usually it is only installed in /dev/sda given by this example:


    boot.loader.grub = {
      # Use grub 2 as boot loader.
      enable = true;
      version = 2;
      
      # Define on which hard drive you want to install Grub.
      device = "/dev/sda"; # here is only one partition given
    };


# links


* [1] <https://nixos.org/wiki/Soft-RAID_mdadm_(/dev/md0),_LVM_(PVs,VGs,LVs)>
* [2] <https://nixos.org/wiki/Encrypted_Root_on_NixOS>