A replica set is great when we understand why we need it and what it cannot do. The different limitations for a replica set are as follows:

• It will not scale horizontally; we need sharding for it
• We will introduce replication issues if our network is flaky
• We will make debugging issues more complex if we use secondaries for reads, and these have fallen behind our primary server

On the flip side, as we explained in previous sections in this chapter, a replica set can be a great choice for replication, data redundancy, conforming with data privacy, backups, and even recovery from errors caused by humans, or otherwise.