Quantify squashfs' efficiency

diff --git a/modules/qemu-vm-isolation.nix b/modules/qemu-vm-isolation.nix
index ed6800ef9281aeff3bb62460d78939fb4c768716..77db2f5f2476b84e6949f8c1e369838e62c06964 100644 (file)
--- a/modules/qemu-vm-isolation.nix
+++ b/modules/qemu-vm-isolation.nix
@@ -68,9 +68,12 @@ in {
       description = ''
         What filesystem to use for the guest's Nix store.
 
-        erofs is more compact than ext4, but less mature.
-
         squashfs is best, but requires patches to set the filesystem label.
+
+        ext4 images are ~4x larger than squashfs images.
+
+        erofs images are only ~2.5x larger than squashfs images, but erofs is less mature than either squashfs or ext4.
+
       '';
       type = lib.types.enum [ "ext4" "erofs" "squashfs" ];
       default = "ext4";