Objective:
This guide provides an overview of the most relevant settings and concepts that control scaling a game's fleet.
Terminology:
Fleets: A collection of physical and cloud servers.
Fleet Regions: Sub-divisions within a Fleet containing regional data centers.
Region Locations: Specific data centers within a region.
Min available servers: Total number of active servers to maintain.
Min servers: Total number of servers to keep from deletion.
Min standby servers: Servers to keep on standby.
Max servers: Maximum server limit.
Shutdown TTL: Time before a machine goes into standby if unused.
Delete TTL: Time a machine stays in standby before being deleted.
Explanation:
What is Scaling?
Scaling is the ability to adjust the number of servers in a group. This can mean adding servers (scaling up) or removing servers (scaling down).
Scaling Up
This typically entails increasing the "Min available servers" and/or "Min servers". This prepares for higher server demand. "Min available servers" is set for predictable scaling - to have servers warmed and ready for players to hop on as quickly as possible. This setting ensures a buffer of active servers will be ready to handle new allocations. For example, setting "Min available servers" to 10 means there will always be 10 servers available for new player sessions. The use case for "Min servers" is often to reserve (in the sense of setting aside) a specific number of servers. The idea is to have a certain capacity available in case of demand during targeted events and so on. Keep in mind the total count of servers can include any operational status except deleted, so it's likely at least some of the servers will be offline or in a cold standby state. "Min Standby Servers" keeps a specific number of servers in a cold standby status or higher if those servers are already active or otherwise operating under another config value.
Scaling Down
This typically entails reducing the "Min available servers" and/or "Min servers". Servers exceeding these settings will eventually enter standby and be deleted. Note also that sometimes the "Disabled delete TTL" value will be lowered to facilitate rapid removal of machines if necessary.