diff --git a/test/command/test_plugin_config_formatter.rb b/test/command/test_plugin_config_formatter.rb
index 28e311401d..a72ea29340 100644
--- a/test/command/test_plugin_config_formatter.rb
+++ b/test/command/test_plugin_config_formatter.rb
@@ -188,7 +188,6 @@ class SimpleServiceDiscovery < ::Fluent::Plugin::ServiceDiscovery
  retry_exponential_backoff_base: float: (2)
  retry_max_interval: time: (nil)
  retry_randomize: bool: (true)
- disable_chunk_backup: bool: (false)
 <secondary>: optional, single
  @type: string: (nil)
  <buffer>: optional, single