What is the primary function of a load balancer?

The primary function of a load balancer is to distribute incoming traffic across multiple servers. This is crucial for ensuring that no single server is overwhelmed by too much traffic, which can lead to performance degradation or system failures. By spreading the load, a load balancer improves availability and reliability, as it allows for a more efficient use of resources and can provide redundancy in case one server goes down. This balancing act not only enhances the user experience by minimizing response times but also optimizes the overall performance of the network or application, ensuring a more seamless operation.

In contrast, other options such as encrypting data at rest, monitoring system performance, and creating backup copies of data are important aspects of IT management but do not align with the primary purpose of a load balancer. Encrypting data focuses on security, monitoring system performance is about maintaining operational efficiency, and creating backups ensures data protection and recovery, which are all separate functions from traffic distribution.