MongoDB Documentation, Release 3.0.4 Chapter 11. Frequently Asked Questions 746 $^{3}$http://blog.mongodb.org/post/137788967/32-bit-limitations $^{4}$https://groups.google.com/forum/?fromgroups#!forum/mongodb-user 5 Each index also has its own namespace. 6 MongoDB database have a configurable limit on the number of namespaces in a database. While data models like this appear to support nested collections, the collection namespace is flat, and there is no difference from the perspective of MongoDB between acme , acme.users , and acme.records . For an example acme.users namespace, acme is the database name and users is the collection name. Period characters can occur in collection names, so that acme.user.history is a valid namespace, with acme as the database name, and user.history as the collection name. Collections are containers for documents that share one or more indexes. Databases are groups of collections stored on disk using a single set of data files. 6 A “namespace” is the concatenation of the database name and the collection names 5 with a period character in between. If you don’t find the answer you’re looking for, check the complete list of FAQs (page 743) or post your question to the MongoDB User Mailing List$^{4}$. This document answers common questions about application development using MongoDB. Note: 32-bit builds disable journaling by default because journaling further limits the maximum amount of data that the database can store. “Blog Post: 32-bit Limitations$^{3}$“ MongoDB is implemented in C++. Drivers and client libraries are typically written in their respective languages, although some drivers use C extensions for better performance. Changed in version 3.0: Commercial support is no longer provided for MongoDB on 32-bit platforms (Linux and Windows). See Platform Support (page 809). 32-bit versions of MongoDB do not support the WiredTiger storage engine. When running a 32-bit build of MongoDB, the total storage size for the server, including data and indexes, is 2 gigabytes. For this reason, do not deploy MongoDB to production on 32-bit machines. If you’re running a 64-bit build of MongoDB, there’s virtually no limit to storage size. For production deployments, 64-bit builds and operating systems are strongly recommended. See also: 11.1.13 What language is MongoDB written in? 11.1.14 What are the limitations of 32-bit versions of MongoDB? 11.2 FAQ: MongoDB for Application Developers 11.2.1 What is a namespace in MongoDB?