Where is collection metadata stored in a sharded cluster?

• A.In a random shard.
• B.On the configuration servers.
• C.In the primary shard.

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Which of the following commands are valid to start a mongod?

• A.mongod --dbpath /data/db --fork
• B.mongod -f /etc/mongod.conf
• C.mongod --logpath /var/log/mongo/mongod.log --dbpath /data/db --fork
• D.mongod --log /var/log/mongo/mongod.log --db /data/db --fork

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Select all true statements regarding to replication in MongoDB.

• A.Replication is the primary mechanism for providing high availability in MongoDB.
• B.In the event of failover, the nodes vote to select the new primary node.
• C.The primary node receives all new write operations, and the secondary nodes stay up to date with the primary.

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There is a collection named products in MongoDB database. Your coworker wants to know how many products are in this collection (number of documents in the collection).
Which query should you use? (select 2)

• A.db.products.find().count()
• B.db.products.total()
• C.db.products.countDocuments()

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Given a companies collection where each document has the following structure:
{ _id: ObjectId('61a8b90c6d5ce6a7d8fef95e'), name: 'Facebook', tag_list: ['facebook', 'college', 'students', 'network'], description: 'Social network' }
Which of the following commands will add new fields to the updated documents?

• A.db.companies.updateMany({ "name": "Facebook" }, { "$push": { "tag_list": "media" } })
• B.db.companies.updateMany({ "name": "Facebook" }, { "$set": { "description": "Social media" } })
• C.db.companies.updateMany({ "name": "Facebook" }, { "$set": { "country": "USA" } })

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