If you could have a wild guess at what GridFS is used for, you’d probably say some kind of file system and you wouldn’t be completely wrong. On the contrary, GridFS isn’t actually a filesystem, but rather a convention for storing large binary data files inside MongoDB.

I haven’t covered storing binary data in MongoDB yet, however it’s possible to store binary data in standard documents, without using GridFS at all. This is possible using the BSON type BinData. It’s not very well supported by the mongo client, however most language drivers have good support, just google “MongoDB BinData”. This is all well and good, in fact if you’re storing under 16MB of data per file, it’s recommended to use this approach. If however you are storing binary files larger than 16MB, GridFS is the way to go. 16MB is the maximum size of a document in MongoDB.

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