How to convert MongoDB storage engine from wiredTiger to In-Memory in replica set?

Question

I have 3 node mongoDB replica set using wiredTiger. I want to use In-Memory engine.So two node will be using in-memory(one of them will be primary) and 3rd will be using WT(using as arbiter). Is it possible to convert storage engine for two of the nodes from WT to in-memory? if yes can please share some resources to follow. Also if there are any best practice for in-memory mongoDB replica set?

Thanks

Answer 1

According to the mongoDB Documentation, your configuration for a replica set is fine and you'll have to follow some rules:

• The instance running with WiredTiger should be hidden
• It's priority should be set at 0 (This is optionnal if you set the property arbiterOnly: true)

To set an instance to inMemory mode from the command line:

mongod --storageEngine inMemory --dbpath <path>

Or, if using the YAML configuration file format:

storage:
   engine: inMemory
   dbPath: <path>