diff --git a/docs/reference/modules/cluster/allocation_awareness.asciidoc b/docs/reference/modules/cluster/allocation_awareness.asciidoc
index 208656126ff..6b896aa4133 100644
--- a/docs/reference/modules/cluster/allocation_awareness.asciidoc
+++ b/docs/reference/modules/cluster/allocation_awareness.asciidoc
@@ -44,7 +44,9 @@ nodes.
 
 Now, if we start two more nodes with `node.rack_id` set to `rack_two`,
 Elasticsearch will move shards across to the new nodes, ensuring (if possible)
-that the primary and replica shards are never in the same rack.
+that no two copies of the same shard will be in the same rack. However if `rack_two`
+were to fail, taking down both of its nodes, Elasticsearch will still allocate the lost
+shard copies to nodes in `rack_one`. 
 
 .Prefer local shards
 *********************************************