There are four primary benefits gained by deploying a replica set:
- High availability: In an ideal scenario, data is available 24/7 (which is 24 hours a day, 7 days a week). Realistically, however, electrical power and network connections go down occasionally (depending on where you live, perhaps more often than not!). Also, of course, servers crash and there are hardware failures. If, however, your data is replicated on other servers, possibly located in different geographic areas, the probability of the data being completely unavailable is considerably reduced.
- Data redundancy: Another aspect of a properly deployed replica set is that data is duplicated, thereby effectively providing a continuous online form of backup. Although it's still considered best practice to make regular offline backups, a properly designed replication strategy can help minimize the need to restore from a backup. The difference between data that is replicated...
