What storage engine does MongoDB use?
WiredTiger
WiredTiger is the default storage engine starting in MongoDB 3.2. It is well-suited for most workloads and is recommended for new deployments. WiredTiger provides a document-level concurrency model, checkpointing, and compression, among other features.
Which are the two storage engines used by MongoDB?
MongoDB supports mainly 3 storage engines whose performance differ in accordance to some specific workloads….WiredTiger Storage Engine
- WiredTiger Storage Engine.
- In-Memory Storage Engine.
- MMAPv1 Storage Engine.
What is WiredTiger storage engine?
WiredTiger is a NoSQL, Open Source extensible platform for data management. The WiredTiger storage engine is the default storage engine starting in MongoDB version 3.2. It provides a document-level concurrency model, checkpointing, and compression, among other features.
What is MMAPv1?
MMAPv1 is MongoDB’s original storage engine based on memory mapped files. It excels at workloads with high volume inserts, reads, and in-place updates. Important. MMAPv1 is supported on 64-bit Intel architectures ( x86_64 ) only.
What is the storage capacity of MongoDB?
Because MongoDB uses a journal file size limit of 100 MB, WiredTiger creates a new journal file approximately every 100 MB of data.
Is MongoDB compressed?
Compression. With WiredTiger, MongoDB supports compression for all collections and indexes. Compression minimizes storage use at the expense of additional CPU. By default, WiredTiger uses block compression with the snappy compression library for all collections and prefix compression for all indexes.
Where are MongoDB databases stored?
mongod defaults the database location to /data/db/ . If you run ps -xa | grep mongod and you don’t see a –dbpath which explicitly tells mongod to look at that parameter for the db location and you don’t have a dbpath in your mongodb. conf , then the default location will be: /data/db/ and you should look there.
Is MongoDB in memory db?
MongoDB is not an in-memory database. Although it can be configured to run that way. But it makes liberal use of cache, meaning data records kept memory for fast retrieval, as opposed to on disk.
Which storage engine supports only collection level locking in MongoDB?
Explanation: MongoDB includes support for two storage engines: MMAPv1, the storage engine available in previous versions of MongoDB, and WiredTiger. 2. Point out the correct statement. Explanation: MMAPv1 provides collection-level locking.
What is journal in MongoDB?
MongoDB uses an on-disk journal to guarantee write operations and provide crash resiliency. MongoDB also creates a journal for every write that includes the exact disk location and the bytes that changed in the write. By default, MongoDB data files are flushed to disk every 60 seconds.
Where is MongoDB data stored?
/data/db directory
By default, MongoDB listens for connections from clients on port 27017, and stores data in the /data/db directory.
What is the maximum size of MongoDB?
The maximum BSON document size is 16 megabytes. The maximum document size helps ensure that a single document cannot use excessive amount of RAM or, during transmission, excessive amount of bandwidth. To store documents larger than the maximum size, MongoDB provides the GridFS API.
Which is the default storage engine in MongoDB?
Starting in MongoDB 3.2, the WiredTiger storage engine is the default storage engine. For existing deployments, if you do not specify the –storageEngine or the storage.engine setting, the version 3.2+ mongod instance can automatically determine the storage engine used to create the data files in the –dbpath or storage.dbPath.
What happens to in memory data in MongoDB?
When an mongod instance shuts down, either as result of the shutdown command or due to a system error, recovery of in-memory data is impossible. Starting in MongoDB 4.2, transactions are supported on replica sets and sharded clusters where: the secondary members use either the WiredTiger storage engine or the in-memory storage engines.
What kind of encryption does MongoDB Enterprise use?
MongoDB Enterprise 3.2 introduces a native encryption option for the WiredTiger storage engine. This feature allows MongoDB to encrypt data files such that only parties with the decryption key can decode and read the data. MongoDB Enterprise on Windows no longer supports AES256-GCM. This cipher is now available only on Linux.
How does block compression work in MongoDB server?
Block compression can provide significant on-disk storage savings, but data must be uncompressed to be manipulated by the server. Via the filesystem cache, MongoDB automatically uses all free memory that is not used by the WiredTiger cache or by other processes.