# Servers and machines

> Documentation for Servers and machines

A machine hosts the allocated server to which game clients connect to play a game session. A machine that hosts game servers must run in a data center.

There are two types of machines:

* A bare metal machine is a rented physical piece of hardware that's running the operating system with the game servers.
* A cloud machine is a virtual machine that's provisioned from a cloud services provider.

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Machines are owned by a fleet and run in a specific [location](/clanforge/legacy/fleets-locations.md). Note that you can only allocate the servers on a machine if that machine belongs to a region. There are normally multiple servers hosted on one machine. Because machines and servers are part of a [fleet](/clanforge/legacy/fleets.md), only servers that belong to that fleet run on a machine.

## Servers on a machine

Clanforge runs the optimal number of game servers on a machine to be [cost-effective](/clanforge/legacy/cost-optimization.md) Learn about optimizing cost without negatively impacting player experience. Clanforge uses the worse-case scenario usage to calculate how many servers to host on a machine. This means that even if the game server experiences a resource usage spike, other game sessions on the machine aren't affected.

Different types of servers consume differing amounts of resources, and this dictates how many servers can fit onto a single machine. For example, training servers can use fewer resources than a full game server, so these servers would be split into different fleets. Refer to [Server slots](/clanforge/legacy/server-slots.md) and [Server density.](/clanforge/legacy/game-server-density.md).