Mongodb 3.0 Production Release released

This release marks the beginning of a new phase, which laid the foundation for making the database powerful, flexible and easy to manage.
Initially, the release version was 2.8, but due to the importance of the changes, it was decided to rename it to 3.0

Major innovations and improvements:
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• Arbitrary storage mechanisms, including WiredTiger. Now api mongo is separated from how the database stores data. This allows you to create new ways to store data, such as InMemory.
• High performance and efficiency. The new WiredTiger storage engine uses document-level locking, which can significantly improve performance. It also uses data and index compression algorithms, which significantly reduces the size of stored data.
• Simplified operations through Ops Manager. It allows you to perform operations such as deploying, scaling, upgrading and backing up with a few clicks or API call. Improved logging system.
• Improved security audit.
• Improved query language and tools. mongoimport, mongoexport, mongodump, mongorestore and mongooplog are now faster. The ability to watch the execution plan before the query using explain.

More information can be found here:
Official Announcement 3.0
Announcement of the main innovations in Mongodb 3.0
Webinar "What's new in Mongodb 3.0"
pdf What's new in Mongodb 3.0


The main improvements come from WiredTiger, but in Mongo 3.0, by default, the main storage is still old (MMAPv1).
To use WT, you need to migrate (if there is data) and run mongod with a special parameter:

mongod --storageEngine wiredTiger --dbpath <newWiredTigerDBPath> 

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The old format (MMAPv1) and new (WT) are not compatible, so manual migration using mongodump, mongoexport or using replica is necessary.