diff --git a/stratisd_cert.py b/stratisd_cert.py
index 01eb679..6ae733a 100644
--- a/stratisd_cert.py
+++ b/stratisd_cert.py
@@ -796,7 +796,7 @@ def test_filesystem_create_specified_size(self):
         fs_name = fs_n()
 
         self._unittest_command(
-            StratisDbus.fs_create(pool_path, fs_name, fs_size="8796093022208"),
+            StratisDbus.fs_create(pool_path, fs_name, fs_size="549755813888"),
             dbus.UInt16(0),
         )