Long term log retention in Loki-stack Helm chart


I am trying to integrate Loki in a k8s environment.

I would like to setup long term retention in s3 for production usage.

First of all, it is not clear for me how to configure storage by loki-stack helm chart.
I am going over this for s3 configuration:

But I cannot find loki configuration options in default values.yaml file and cannot see a clear example for storage/schema configuration in loki-stack helm installation.

storage_config exists in loki-distributed. Then I am also not clear on difference of loki-distributed and loki-stack helm charts. Is that simply ok to use loki-distributed instead of loki-stack?

Second, how do I configure long-term log retention for production (simply keep all lifetime logs in s3)?

Is that stores all the logs from 2020-05-15? How is duration period 168h (default value) related with retention?

  - from: 2020-05-15
    store: boltdb-shipper
    object_store: s3
    schema: v11
      prefix: index_
      period: 168h