diff --git a/prometheus/defaults/main.yml b/prometheus/defaults/main.yml
index 83753e50..9348ac5f 100644
--- a/prometheus/defaults/main.yml
+++ b/prometheus/defaults/main.yml
@@ -11,4 +11,4 @@ prometheus_confdir: '/opt/prometheus/conf'
 prometheus_cmd: '{{ prometheus_dist_dir }}/{{ prometheus_dir }}/prometheus'
 prometheus_loglevel: info
 prometheus_http_port: 9090
-prometheus_opts: '--storage.tsdb.retention=120d'
+prometheus_opts: '--storage.tsdb.retention=360d'