REST api is not working for datapath change

I am using curl to change the datapath and index. it is working for index path change but not for datapath.
couchbase version is : 4.0

below is the command used
curl -u Administrator:password -X POST http://localhost:8091/nodes/self/controller/settings -d data_path=/Database/data -d index_path=/Database/data

also i am not getting any error.

Indeed this endpoint is just for the Index path: http://developer.couchbase.com/documentation/server/4.1/rest-api/rest-node-index-path.html
Are you running it to a live node?

No . i was just automating the configurations and found that some part of docs i can see rest api is there for datapath. thanks for confirming.