If the intent were to copy some portion of the data or the entire data to an index with the same settings/mappings as that of the original index one could use the clone
api to achieve the same. Something like below:
POST /<index>/_clone/<target-index>
OR
PUT /<index>/_clone/<target-index>
However if the intent is to copy the data to a new index with the different settings/mappings than the original index one could use the reindex
api to achieve the same. Something like below:
POST _reindex/
{
"source": {
"index": "source_index",
"type": "source_type",
"query": {
// add filter criteria
}
},
"dest": {
"index": "dest_index",
"type": "dest_type"
}
}
*Note: In case of reindex api the target index has to be created prior to actual api call.
For further reading on difference between clone and reindex refer What's the difference between cloning and reindexing an index in Elasticsearch?