diff --git a/README.md b/README.md
index a487f68..eeec03d 100644
--- a/README.md
+++ b/README.md
@@ -12,3 +12,4 @@ docker compose run --build --rm cports
 ```
 
 - your cports repo will be in /cports, just do setup normally after that
+- make sure you have sane `ulimits -n`, docker for some reason is setting it as `1073741816` lately, and that makes builds take minutes.