Note that mapper attachments plugin is deprecated and is replaced by ingest-attachment.
This later plugin "only" extracts text from your binary doc without storing it in elasticsearch.
Storing binary documents is not ideal. Imagine that you store a MP4 movie in a Lucene segment (well 4gb-10gb), it does not really make sense. Elasticsearch has not been designed for that purpose.
I like in such a case using another BLOB storage:
- HDFS
- CouchDB
- S3
...
And just index the content in elasticsearch with a URL to the source blob.
I hope it makes sense.