From: Scott Worley <scottworley@scottworley.com>
Date: Mon, 8 Jun 2026 06:41:38 +0000 (-0700)
Subject: Quantify squashfs' efficiency
X-Git-Url: http://git.scottworley.com/nixos-qemu-vm-isolation/commitdiff_plain/121d6b078ec1aba8fdb4aa6058f649fe307b8fb7?hp=b2cb606e5daf3b4825d2d9e423fe40ba90d755f1

Quantify squashfs' efficiency
---

diff --git a/modules/qemu-vm-isolation.nix b/modules/qemu-vm-isolation.nix
index ed6800e..77db2f5 100644
--- 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";