When traffic to a web application spikes suddenly, what is the method of distributing the load by adding one server at a time called?
A question about identifying the technique of increasing server count to handle growing load.
Scale up (vertical scaling)
This is incorrect. Scaling up means increasing the CPU or memory of a single server to boost its performance. It strengthens one machine rather than adding more machines, so it does not match the description of adding servers one at a time.
Failover
This is incorrect. Failover is a mechanism that automatically switches to a standby system when a failure occurs. It is designed for fault recovery, not for adding servers in response to increased load.
Scale out (horizontal scaling)
Correct. Scale out (horizontal scaling) is the method of increasing the number of servers with the same role to distribute the load. In the cloud, Auto Scaling combined with a load balancer enables automatic increases and decreases in capacity based on demand, and also reduces single points of failure.
Snapshot
This is incorrect. A snapshot is a backup feature that captures a point-in-time copy of a volume or dataset. It has nothing to do with adding servers to distribute load.
The contrast between scale out (horizontal = increasing server count) and scale up (vertical = strengthening one server) is frequently tested. The cloud excels at scale out using Auto Scaling + a load balancer. Vertical scaling tends to leave a single point of failure.