Explanation: During startup of a virtual server, or whenever the state of a virtual server changes, the virtual server can initially use the round-robin method to distribute the client requests among the physical servers. This type of distribution, referred to as startup round robin, helps prevent unnecessary load on a single server as the initial requests are served. After using the round-robin method at the startup, the virtual server switches to the loadbalancing method specified on the virtual server
Correct Answer: D. Round-robin
Short Explanation with reference:
A load-balancing vServer is a virtual server that distributes the incoming traffic among a group of services that provide the same content or functionality. A load-balancing vServer can use different load-balancing methods to select the best service for each request, based on various criteria, such as availability, performance, or load. The least bandwidth load-balancing method selects the service that is currently handling the least amount of traffic, measured in megabits per second.
However, during the startup of a vServer, the least bandwidth load-balancing method is not used by default. This is because the Citrix ADC appliance does not have enough data to calculate the bandwidth usage of each service at the beginning. Therefore, the appliance uses the round-robin load-balancing method by default, which selects the services in a circular order, without any weighting or priority. The round-robin load-balancing method is also used as a fallback method when other load-balancing methods fail or are not applicable.
Therefore, the correct answer is D. Round-robin.
Load balancing methods | NetScaler : How Load Balancing Methods Work - Citrix Customer Support