I’ve started Prometheus with
--storage.tsdb.retention.time=30d and --storeage.tsdb.retention.size=200GB. If I check the status page, I see

Storage retention      30d or 200GiB

so I know the config has taken effect. Unfortunately, I’m still only retaining 15d worth of data. If did a du -h of the data dir and it’s only taking up 125GB, so it shouldn’t be limited by the size. What else do I need to do to get Prometheus to retain more data?