We are using elastic search almost as a cache, storing documents found in a time window. We continuously insert a lot of documents of different sizes and then we search in the E
I would fire up an additional ES instance and have it form a cluster with your current node. Then I would split the work between the two machines, use one for indexing and the other for querying. See how that works out for you. You might need to scale out even more for your specific usage patterns.