Atomicity of Model.create in Mongoose when passing an array of documents
MongoDB Wire Protocol accepts either single document or multiple documents with OP_INSERT. However, on the server they are still inserted one at a time.
In other words, if the server were to crash part-way through the insert, some documents would be inserted and others would not be. Within each document you are guaranteed consistent view of it - either it's all inserted or it's not. But for multiple documents no such guarantee exists.