ES-Backup -Restore

Elastic Stack Elasticsearch
1

Hi,
i have two questions.

       1.How to use (Close/Open) API in ES.

               i have executed below queries.
                     curl  -XPOST 'http://localserver:9200/db1/

_close'

                                   AND

curl -XPOST 'http://localserver:9200/db1/_close'