diff --git a/operating-systems/buer/file-systems.scm b/operating-systems/buer/file-systems.scm
new file mode 100644
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--- /dev/null
+++ b/operating-systems/buer/file-systems.scm
@@ -0,0 +1,104 @@
+;; based on https://codeberg.org/squishypinkelephant/guix-random-junk
+
+;; how to guix: / as tmpfs
+
+;; /var/guix is REQUIRED to perform rollbacks
+;; create the folders /gnu/persist/etc/ssh /gnu/persist/etc/wireguard and
+;; the file /gnu/persist/etc/machine-id for dbus
+
+(define-module (buer file-systems)
+  #:use-module (gnu system file-systems)
+
+  #:export (rootfs
+            bootfs
+            file-systems))
+
+;;; reminder: Send a patch to guix to make file-system-options receive a
+;;; list-of-strings
+
+(define rootfs
+  (file-system
+       (device (file-system-label "root"))
+       (mount-point "/")
+       (type "tmpfs")
+       (options "mode=755")))
+
+(define bootfs
+  (file-system
+    (device (file-system-label "root")
+     (type "btrfs")
+     (mount-point "/boot")
+     (dependencies (list rootfs))
+     (flags '(no-atime))
+     (options (format #f "compress=zstd:7,~
+                          discard=async,~
+                          ssd,~
+                          subvol=@boot")))))
+
+(define file-systems
+  (cons* rootfs
+         ;; /gnu/store
+         (file-system
+           (device (file-system-label "root"))
+           (type "btrfs")
+           (mount-point "/gnu/store")
+           (needed-for-boot? #t)
+           (dependencies (list rootfs))
+           (flags '(read-only bind-mount no-atime))
+           (options (format #f "compress=zstd:7,~
+                                discard=async,~
+                                ssd,~
+                                subvol=@gnu/store")))
+         ;; /gnu/persist
+         (file-system
+           (device (file-system-label "root"))
+           (type "btrfs")
+           (mount-point "/gnu/persist")
+           (needed-for-boot? #t)
+           (dependencies (list rootfs))
+           (flags '(no-atime bind-mount))
+           (options (format #f "discard=async,~
+                                ssd,~
+                                subvol=@gnu/persist")))
+         ;; /home
+         (file-system
+           (device (file-system-label "root"))
+           (type "btrfs")
+           (mount-point "/home")
+           (dependencies (list rootfs))
+           (flags '(no-atime bind-mount))
+           (options (format #f "compress=zstd:7,~
+                                discard=async,~
+                                ssd,~
+                                subvol=@home")))
+         ;; /var/guix
+         (file-system
+           (device (file-system-label "root"))
+           (type "btrfs")
+           (mount-point "/var/guix")
+           (dependencies (list rootfs))
+           (flags '(no-atime))
+           (options (format #f "compress=zstd:7,~
+                                discard=async,~
+                                ssd,~
+                                subvol=@var/guix")))
+         ;; /var/log
+         (file-system
+           (device (file-system-label "root"))
+           (type "btrfs")
+           (mount-point "/var/log")
+           (dependencies (list rootfs))
+           (flags '(no-atime))
+           (options (format #f "compress=zstd:7,~
+                                discard=async,~
+                                ssd,~
+                                subvol=@var/log")))
+         ;; /boot
+         bootfs
+         (file-system
+          (device (file-system-label "esp"))
+          (type "vfat")
+          (dependencies (list bootfs))
+          (mount-point "/boot/efi")
+          (create-mount-point? #t))
+         %base-file-systems))