Index Lifecycle Policy doesn't work

[Moritz_Kiesewetter]

Hey Guys,
i tought i'd like to try the Index Lifecycle Policies. But i'm pretty sure i've done something wrong, because the Index to which i assigned it is now 37GB instead of a max of 20GB.
I Created one which looks like this

{
    "policy": {
        "phases": {
            "hot": {
                "min_age": "0ms",
                "actions": {
                    "rollover": {
                        "max_size": "20gb"
                    },
                    "set_priority": {
                        "priority": 100
                    }
                }
            },
            "delete": {
                "min_age": "90d",
                "actions": {
                    "delete": {}
                }
            }
        }
    }
}

I also attached it to my index template.

{
"settings": {
"index": {
"lifecycle": {
"name": "RollOver3Months",
"rollover_alias": "logstashprodal"
},
"number_of_shards": "3",
"provided_name": "logstashprod-001",
"creation_date": "",
"priority": "100",
"number_of_replicas": "1",
"uuid": "DlQVGsM5RaunnSacdmaghw",
"version": {
"created": "6080199"
}

Can anyone help me why this doesn't work? I'm really new to this topic.

Thanks in advance!

[Moritz_Kiesewetter]

If i check my ilm with GET logstashprod-001/_ilm/explain

I get:

{
  "indices" : {
    "logstashprod-001" : {
      "index" : "logstashprod-001",
      "managed" : true,
      "policy" : "RollOver3Months",
      "lifecycle_date_millis" : 1571126532382,
      "phase" : "hot",
      "phase_time_millis" : 1572868546760,
      "action" : "unfollow",
      "action_time_millis" : 1572868546817,
      "step" : "wait-for-follow-shard-tasks",
      "step_time_millis" : 1572868546845,
      "phase_execution" : {
        "policy" : "RollOver3Months",
        "phase_definition" : {
          "min_age" : "0ms",
          "actions" : {
            "rollover" : {
              "max_size" : "20gb"
            },
            "set_priority" : {
              "priority" : 100
            }
          }
        },
        "version" : 11,
        "modified_date_in_millis" : 1572860883160
      }
    }
  }
}

So it seams like it is actually managed by it.

[Moritz_Kiesewetter]

Now it 47GB , i need help guys!