Serverpauser
Serverpauser - Smart Pause for Minecraft Server
This mod is a simple server-side solution that automatically stops game ticks when there are no active players on the server. When all users leave the game, the mod suspends the execution of all time-based processes.
Thanks to this function, the day-night cycle completely stops, days don't progress, and all events dependent on game time are halted. This is especially useful for servers with modifications that add special events on certain days, and also helps reduce hardware load from constantly running automatic farms in loaded chunks.