Direct answer
Lag that appears at a consistent real-world time may be caused by scheduled backups, restarts, database jobs or player peaks. Lag linked to an in-game day/night cycle instead suggests time-specific mobs or automation.
How to check it
- Write down the exact timezone and timestamps for multiple lag events.
- Compare the schedule with backups, world saves, plugin sync tasks and host maintenance jobs.
- Separately check the Minecraft daytime and entity/farm activity when the lag begins.
- Capture a spark profile and system disk/CPU metrics during the repeatable period.
What to change
- Stagger expensive scheduled jobs and ensure backups use a consistent safe procedure.
- If mob spawning or farms drive the in-game cycle spike, measure those entities rather than disabling an unrelated plugin.
- Investigate host I/O wait and CPU steal when spikes coincide with provider-level activity.
Software and version notes
Real-world time and in-game time are different causes. Looking only at the gamerule doDaylightCycle (or its version-specific name) cannot diagnose nightly scheduled backups.
Practical example: Example: TPS drops every evening at 20:00 local time, including when Minecraft is at noon. That points toward a backup, scheduled command or host resource contention rather than the day/night mob cycle. If spikes recur at sunset in-game regardless of real time, investigate mob spawning or player farms instead.
Verify the result
- Compare several cycles after the change, matching both clock time and in-game conditions.
- Verify that the scheduled tasks still run and backups remain restorable.