My RAM keeps rising and never drops (memory leak) — is that normal? How do I fix it?
RAM that climbs steadily and never drops can look alarming, but it's only a real problem if it ends in a crash. Java naturally holds memory high — a true memory leak is when usage keeps rising until the server runs out and crashes, usually because of a specific mod or plugin.
Is it actually a leak?
First, tell the difference:
- Just sitting high — normal JVM behavior, nothing to fix.
- Climbing steadily until it crashes with OutOfMemory — that's a leak worth chasing.
How to fix a leak
- Confirm it truly crashes — look for OutOfMemory in the Console, rather than just high-but-stable usage.
- Run a spark heap report with
/spark heapsummaryto see what's holding memory. - Update or remove the suspect mod or plugin.
- Set a sensible RAM buffer on the Settings page so a spike doesn't hard-crash the server.
- Schedule a periodic restart (via the Schedules tab) to clear accumulated memory as a stopgap.
Tip: High-but-stable RAM is fine — only a steady climb that ends in an OutOfMemory crash points to an actual leak.
Frequently asked questions
My RAM is high but the server never crashes — is that a leak? No. That's normal Java behavior. A leak specifically ends in an OutOfMemory crash.
How do I find which mod is leaking? Run /spark heapsummary to see what's holding memory, then update or remove the suspect and test.
More in RAM / Memory Behavior
- Why does my server use so much RAM even when idle or with few players?
- My server restarts with OutOfMemory every few hours — how do I fix it?
- Where do I set RAM buffer, minimum RAM, Xms/Xmx, and what values?
- Why does my server show less RAM than I paid for (e.g. 4GB shows as 2GB)?
- How much RAM should a server use on boot (e.g. 8GB booting at 6GB)?
- Can I limit or reduce RAM usage without upgrading?