Question

You can inspect __________ to check the amount of mapped memory that mongod is using.

(a) mem.mapped

(b) memory.resident

(c) mem.resident

(d) all of the mentioned

The question was asked by my school principal while I was bunking the class.

The doubt is from Optimization Strategies in chapter Monitoring MongoDB and Optimization Strategies for MongoDB of MongoDB

Answer 1

The correct answer is (a) mem.mapped

To elaborate: If this value is greater than the amount of system memory, some operations will require a page faults to read data from disk.