Sleep and wake

An empty server does not have to hold CPU and memory. Carbon Panel can pause a server in place or stop it entirely, then bring it back when a player joins.

The three layers

Layer	What happens	Memory	CPU	Wake
Native pause	Minecraft stops ticking while empty, but the container keeps running.	Unchanged	Near zero	Instant
Freeze	The container process is suspended with the cgroup freezer.	Unchanged	Near zero	Instant
Deep sleep	The container is stopped.	Released	Zero	After a container start

Each layer is independent. They compose: a server can use native pause on its own, or combine it with freeze or deep sleep.

Native pause

Minecraft 1.21.2 and later pause ticking when no players are online. The relevant setting is pause-when-empty-seconds in server.properties, which defaults to 60 seconds. Because the server keeps running and keeps answering server-list pings, this needs no panel configuration and no proxy.

Freeze on idle

In the server’s Settings → Sleep & Deep Sleep, enable Freeze on Idle and set Idle minutes before freeze.

The panel suspends the container after that many idle minutes. The process stays in memory, so the first join resumes in milliseconds. The default timeout is 10 minutes; a value of 0 uses the default.

Freeze needs a daemon and host that allow the freezer. When the panel cannot freeze a container it reports the failure and leaves the server running.

Deep sleep on idle

Enable Deep Sleep on Idle and set Idle minutes before deep sleep.

The panel stops the container after that many idle minutes. The JVM exits, so the memory is returned to the host. On a join, the panel starts the container and holds the connection while the server boots (up to about 25 seconds). The default timeout is 30 minutes; a value of 0 uses the default.

Note

Wake-on-join needs the proxy to be listening: a direct connection to a stopped container has nothing to accept it. Without the proxy, start a deep-sleeping server from the panel or the dashboard first.

What counts as idle

The panel samples the player count. A server becomes a sleep candidate only when its player count has been zero for the whole timeout. A join resets the idle clock.

Server-list pings do not count as joins and never wake a server. Status queries and the panel’s own monitoring do not reset the idle clock either.

Waking

• A player login through the proxy wakes a frozen or deep-sleeping server.
• Starting the server from the panel or dashboard also wakes it.
• A scheduled task that starts the server wakes it.
• Applying a staged update handles the state deliberately: a deep-sleeping server receives the batch without booting, a running server restarts once, and a frozen server is stopped, started, and left running. See Staged updates.

Choosing a mode

If you want to…	Use
Save CPU with zero visible downtime	Native pause, optionally freeze.
Return memory to the host on a quiet server	Deep sleep.
Keep a server ready for instant joins	Native pause, or freeze at most.
Run many small servers on limited RAM	Deep sleep.
Keep a server reachable from voice chat or map mods	Do not deep sleep it; those ports are published directly and cannot wake it.

Caution

Deep sleep adds a cold start to the first join after idling. Players see a connection hold while the server boots, and a client may need to retry. Say so in your server’s MOTD or community rules if players are not used to it.