hot plug a node w/ MongoDB

Question

We are evaluating MongoDB with my team and I have a couple questions that I'm sure are answered somewhere on the web but I couldn't find the answers...

1) Can we hot plug a data node in the MongoDB cluster? If we can how difficult is it? 2) It seems like MongoDB works from the HDD, but does it have a caching strategy to avoid hitting the disk w/ every requests? Is the caching strategy configurable?

Thanks for your help

Answer 1

1) Yes, you can add members to the replica set on the go.

2) MongoDB uses memory-mapped files. The interval at which the data is flushed to the disk (fsync) can be configured and is 60 seconds by default.

MongoDB official documentation should provide you with answers to most of the questions, that might arise during testing.