MongoDB 数据库中的数据如何存储在磁盘上？

Question

I know that MongoDB accepts and retrieves records as JSON/BSON objects, but how does it actually store these files on disk? Are they stored as a collection of individual *.json files or as one large file? I have a hunch as to the latter, since the MongoDB docs state that it works best on systems with ext4/xfs , which are better at handling large files. Can anyone confirm?

Answer 1

A given mongo database is broken up into a series of BSON files on disk, with increasing size up to 2GB. BSON is its own format, built specifically for MongoDB.

These slides should answer all of your questions:

http://www.slideshare.net/mdirolf/inside-mongodb-the-internals-of-an-opensource-database

Answer 2

MongoDB stores the data on the disk as BSON in your data path directory, which is usually /data/db . There should be two files per collection there, collection.0 , which stores the data (and that integer is then incremented as needs be) and collection.ns which stores the namespacing metadata for the collection.

Answer 3

BSON 格式的详细文档可以在这里找到： http : //bsonspec.org/

Answer 4

最高 mongodb 3.0 http://blog.mongolab.com/2014/01/how-big-is-your-mongodb/如果您在 MongoDB 3.0 中打开了wiredtiger 存储引擎，它将使用wiredtiger 存储模型http://docs。 mongodb.org/v3.0/core/storage/#storage-wiredtiger