We are planning to store millions of documents in MongoDB and full text search is very much required. I read Elasticsearch and Solr are the best available solutions for full
Mongo is not at al good for fulltext search. Obviously you need to index you fields for fast searching, and indexing fields containing BIG data (long long strings) will be failed in mongo. it has a limit of 1k for index, if you have content more thn 1k, it will be ignored by index and will not be displayed in your search results. obviously if you are trying to perform a full text search for your articles, mongo is not at al a good choice.