diff --git a/f-coreos.bu b/f-coreos.bu
index a4ef461..411bc66 100644
--- a/f-coreos.bu
+++ b/f-coreos.bu
@@ -27,6 +27,24 @@ passwd:
         - ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJ4G1BFBIcYZroqWvjC7ZlT0rL5cSGg1JQK1BtWCFgff cphipps@basement-pc.home.cahaa.net
 
 storage:
+  disks:
+    - # The link to the block device the OS was booted from.
+      device: /dev/sda
+      # We do not want to wipe the partition table since this is the primary
+      # device.
+      wipe_table: false
+      partitions:
+        - number: 4
+          label: root
+          # Allocate at least 8 GiB to the rootfs. See NOTE above about this.
+          size_mib: 0
+          resize: true
+  filesystems:
+    - device: /dev/disk/by-partlabel/root
+      wipe_filesystem: true
+      format: btrfs
+      label: root
+
   files:
     # Set the machine hostname
     - path: /etc/hostname