diff --git a/chapter08/systemd.xml b/chapter08/systemd.xml
index 1e17c60ce..989082419 100644
--- a/chapter08/systemd.xml
+++ b/chapter08/systemd.xml
@@ -228,7 +228,11 @@ ninja test</userinput></screen>
          after initializing the system with systemd.  -->
     <para>One test named <literal>systemd:core / test-namespace</literal>
     is known to fail in the LFS chroot environment.  Some other tests may
-    fail because they depend on various kernel configuration options.</para>
+    fail because they depend on various kernel configuration options.
+    The test named <literal>systemd:test / test-copy</literal> may time out
+    due to an I/O congestion with a large parallel job number, but it
+    would pass if running alone with
+    <command>meson test test-copy</command>.</para>
 
     <para>Install the package:</para>