diff --git a/Optimization.md b/Optimization.md
index 8ed14ea..2bffc68 100644
--- a/Optimization.md
+++ b/Optimization.md
@@ -50,6 +50,7 @@ copy_1 = 7                # create 1 x 7 = 7 actual volumes
 copy_2 = 6                # create 2 x 6 = 12 actual volumes
 copy_3 = 3                # create 3 x 3 = 9 actual volumes
 copy_other = 1            # create n x 1 = n actual volumes
+threshold = 0.9           # create threshold
 ```
 
 ## Increase concurrent reads