diff --git a/nginx.conf b/nginx.conf
index be0c71c..a37e92c 100644
--- a/nginx.conf
+++ b/nginx.conf
@@ -57,6 +57,9 @@ http {
 
   # Speed up file transfers by using sendfile() to copy directly
   # between descriptors rather than using read()/write().
+  # For performance reasons, on FreeBSD systems w/ ZFS 
+  # this option should be disabled as ZFS's ARC caches
+  # frequently used files in RAM by default.
   sendfile        on;
 
   # Tell Nginx not to send out partial frames; this increases throughput