Thank you Mark! 
No troubleshooting, but I am currently using Elasticsearch as a search index, and am building out some tools to support its use. I have some concerns on deleting a very large Elasticsearch index.
It might be helpful to get a short blurb on how it operates. For example, even if the delete of an index is very fast / lightweight, if it deletes docs one by one before returning that may still be an issue for me as the count of indexed objects / total indexed size continues to grow.