change elasticsearch.index-name not working

[geosmart]

I use janusgraph 0.3.0
and store the graph in hbase an elasticsearch,

and it create 3 index in es with prefix janusgraph like this:

janusgraph_vertex_index
janusgraph_fulltext_index 
janusgraph_edge_index

my question is how can to change the index prefix with a custom string

as official doc-elasticsearch says

JanusGraph index.[X] and index.[X].elasticsearch options
JanusGraph only uses default values for index-name and health-request-timeout. See Configuration Reference for descriptions of these options and their accepted values.

index.[X].elasticsearch.index-name
index.[X].elasticsearch.health-request-timeout

I change it by index.search.elasticsearch.index-name=custom_str
but it just not working!

any help is appreciate.

[li-boxuan]

This is a GLOBAL_OFFLINE config which requires

These options can only be changed for the entire database cluster at once when all instances are shut down