diff --git a/script/cache_critical_dns b/script/cache_critical_dns
index 0b1ecbe343c..c7b8f17442a 100755
--- a/script/cache_critical_dns
+++ b/script/cache_critical_dns
@@ -15,6 +15,7 @@ CRITICAL_HOST_ENV_VARS = %w{
   DISCOURSE_DB_REPLICA_HOST
   DISCOURSE_REDIS_HOST
   DISCOURSE_REDIS_SLAVE_HOST
+  DISCOURSE_REDIS_REPLICA_HOST
 }
 
 def log(msg)