diff --git a/notes.md b/notes.md
index 853b0d1b8..b8cba0bc3 100644
--- a/notes.md
+++ b/notes.md
@@ -7,3 +7,6 @@
 - leak page aligned object locations
 - deduce sup-page granular objects (how?)
 - intel CPU needed (8th-14th gen) (?)
+
+## FD limit
+- Must increase number of allowed FDs for spray to work. E.g. with `ulimit -n $(ulimit -n -H)`