diff --git a/script/cache_critical_dns b/script/cache_critical_dns
index 613a3c7b2b5..ce032c4ffd5 100755
--- a/script/cache_critical_dns
+++ b/script/cache_critical_dns
@@ -11,7 +11,7 @@ HOSTS_PATH = "/etc/hosts"
 
 CRITICAL_HOST_ENV_VARS = %w{
   DISCOURSE_DB_HOST
-  DISCOURSE_DB_BACKUP_HOST
+  DISCOURSE_DB_REPLICA_HOST
   DISCOURSE_REDIS_HOST
   DISCOURSE_REDIS_SLAVE_HOST
 }