diff --git a/roles/monitor/defaults/main.yml b/roles/monitor/defaults/main.yml
index da5429be6d118c944951ca248ba72a3516b5fdba..a01e536efdc80febe49518d2119e96978c0db426 100644
--- a/roles/monitor/defaults/main.yml
+++ b/roles/monitor/defaults/main.yml
@@ -3,3 +3,5 @@
 graphite_secret_key: "changeme"
 grafana_secret_key: "changeme"
 test_source_stream: "/test.ogg"
+prometheus_tsdb_retention_time: "180d"
+
diff --git a/roles/monitor/templates/prometheus.default.j2 b/roles/monitor/templates/prometheus.default.j2
index 04ff5594fefc16ad710b6f4fb406900c564c8fc7..7d7f42bfb868fa4ca61217ffad342328528760a1 100644
--- a/roles/monitor/templates/prometheus.default.j2
+++ b/roles/monitor/templates/prometheus.default.j2
@@ -1,2 +1,2 @@
-ARGS="--web.external-url=https://monitor.{{ public_domain }}"
+ARGS="--web.external-url=https://monitor.{{ public_domain }} --storage.tsdb.retention.time={{ prometheus_tsdb_retention_time }}"