diff --git a/docs/tuning.md b/docs/tuning.md
index f491ae9b95c08b757bbd3630575c5eee1a89e40e..f33fda37ebaba4d6b34d775bdf0190c987a3da83 100644
--- a/docs/tuning.md
+++ b/docs/tuning.md
@@ -67,7 +67,7 @@ The [Kryo documentation](http://code.google.com/p/kryo/) describes more advanced
 registration options, such as adding custom serialization code.
 
 If your objects are large, you may also need to increase the `spark.kryoserializer.buffer.mb`
-system property. The default is 32, but this value needs to be large enough to hold the *largest*
+system property. The default is 2, but this value needs to be large enough to hold the *largest*
 object you will serialize.
 
 Finally, if you don't register your classes, Kryo will still work, but it will have to store the