Setup Big Server

Big Server Performance

For servers with many players online at once, or with modest hardware. The apocalypse still feels like Standard, but the mod does less work per player, keeps fewer zombies loaded, and holds events to a fixed ceiling.

Read Before You Start if this is your first guide.

Why Player Count Matters

• Every survival player rolls for waves separately, and every roll that succeeds searches for spawn spots. Twice the players means twice the work.
• The nearby cap is per player. Ten players spread out with a cap of 50 can mean 500 zombies loaded at once, plus vanilla mobs.
• Hordes and blood moons are server-wide: every online player gets event waves during the same event.
• Block breaking, block placing, and towering add per-zombie checks, so their cost grows with the number of loaded zombies.

Commands

Run these in order:

/za preset standard
/za spawn interval 200
/za spawn amount 1
/za spawn attempts 5
/za spawn max 30
/za spawn nightmax 20
/za events spawninterval 40
/za events amount 3
/za bloodmoon amount 3
/za spawn effects off
/za spawn debug off

• preset standard first, because presets set the interval and attempts back to their normal values.
• interval 200 checks every 10 seconds instead of every 6. amount 1 and attempts 5 cut the spawn-spot searching per successful check to a quarter of Standard's (5 tries instead of 20).
• max 30 and nightmax 20 are the most important lines: they decide how many zombies can be loaded per player, day and night. The night cap also holds during hordes and blood moons at night, unless you set a separate blood moon cap with /za spawn bloodmoonmax.
• events spawninterval 40 checks every 2 seconds during events instead of every second. It is the same setting as /za spawn eventinterval.
• effects off drops the spawn sound and smoke, which saves a little network traffic.

Config File

Edit with the server stopped. These go on top of the Standard values:

# [general]
enableDebugLogging = false
# [dayspawning]
daySpawnInterval = 200
zombiesPerSpawn = 1
spawnAttemptsPerZombie = 5
maxDayZombiesPerPlayer = 30
# [nightspawning]
maxNightZombiesPerPlayer = 20
# [horde]
eventSpawnInterval = 40
hordeZombiesPerSpawn = 3
# [bloodmoon]
bloodMoonZombiesPerSpawn = 3
# [effects]
enableSpawnEffects = false

What To Expect

• Days: every 10 seconds each player has a 50% chance of one zombie, up to 30 zombie-class mobs around that player.
• Nights: a 75% chance every 10 seconds, up to 20 around each player.
• Hordes and blood moons: a check every 2 seconds, a wave on every check at night, 3 zombies each. The 20-zombie night ceiling is reached quickly, and new zombies only replace the ones players kill.
• Players together share one crowd, because the cap counts every zombie-class mob near each player, vanilla ones included.

If You Use Siege Features Or Hunting

Keep their checks slow and their reach small:

/za breaking interval 200
/za breaking range 1
/za placing interval 200
/za placing limit 4
/za towering interval 40
/za towering radius 2.25
/za towering maxperplayer 1
/za hunt totalcap 10

Avoid /za towering unlimited and /za towering interval 1 on a busy server. Very tall towers are expensive for Minecraft itself.

Things To Leave Alone

Setting	Why
/za spawn range	Keep 30 or lower. A wider range searches a bigger area and counts zombies over a bigger box for every player.
/za spawn nether and /za spawn end	Off by default. Turning them on adds custom spawning in more places.
/za spawn debug	Keep it off except while troubleshooting. It writes extra spawn and event details to the log.
/za events multiplier	Raising it does not cost CPU by itself, but it fills the cap faster.

Tuning

Symptom	Try
Still too many zombies	/za spawn max 20 and /za spawn nightmax 15
Too quiet for players	/za spawn chance 0.75 (more waves, same ceiling)
Lag spikes when a horde starts	/za events spawninterval 60
Lag only on blood moons	/za bloodmoon amount 2 or /za bloodmoon chance 0.05
Lag around one player's base	Check /za towering and /za breaking; lower /za towering maxperplayer

Change one setting at a time and watch the server tick time with a profiler mod during a real horde with your usual player count.

Undo

/za preset standard restores the interval, attempts, wave sizes, and caps, including the night cap. Then turn the spawn effects back on:

/za spawn effects on