Smooth migration from one boltdb-shipper shared-store to another

Hi there!

As I understand it the recommended way to migrate loki storage is by using a new schema.
Currently we store both index and chunks on the filesystem and we want to migrate to S3.
I can add a new schema and Loki ships its chunks to S3 as expected. The missing part is how to migrate the boltdb_shipper as I can only specify one boltdb-shipper as far as I know.

So I guess I would need to have a config like this:

    config:
      storage_config:
        s3:
          endpoint: xxx
          bucketnames: staging-loki-data
          s3forcepathstyle: true
          http_config:
            insecure_skip_verify: true
        boltdb_shipper1:
          shared_store: filesystem
        boltdb_shipper2:
          shared_store: s3
        filesystem:
          directory: /data/loki/chunks
      schema_config:
        configs:
          - from: 2022-02-14
            store: boltdb-shipper1
            object_store: filesystem
            schema: v11
            index:
              prefix: index_
              period: 24h
          - from: 2022-04-14
            store: boltdb-shipper2
            object_store: s3
            schema: v11
            index:
              prefix: index_
              period: 24h

Do you have any hint on how to accomplish a smooth migration? Otherwise I’d have to copy chunks and index manually, probably with some data loss