A server cluster in computing refers to a group of linked servers that work together to improve performance, reliability, and availability. This configuration allows multiple servers to handle tasks and share resources, ensuring that if one server fails, others can take over without disruption. Server clustering is commonly used for load balancing, failover, and providing high availability for critical applications. By linking multiple servers, organizations can enhance their processing power and ensure continuous service to users, making it a vital component in data centers.