MongoDB
- stores JSON as BSON (binary JSON that interprets types. similar to protobuf)
- for performance, it is important to create indexes
- The maximum BSON document size in MongoDB is 16 MB.
GridFS
For files larger than 16 MB, MongoDB provides a convention called GridFS, which is implemented by all MongoDB drivers. GridFS automatically divides large data into 256 KB pieces called chunks and maintains the metadata for all chunks. GridFS allows for retrieval of individual chunks as well as entire documents. For example, an application could quickly jump to a specific timestamp in a video. GridFS is frequently used to store large binary files such as images and videos directly in MongoDB, without offloading them to a separate filesystem
Replica Sets
Are used for persistance, not for performance.
- consists on multiple nodes which contain a copy of the database.
- there is only one primary node and multiple secondary nodes.
- writes and reads only go to the primary.
- secondary nodes are only for backup
Reference
Sharding
- splits database in multiple replica sets for scalability.