Hyronic Mcmmo Docspersistent_data.yml
Which mcMMO mob metadata is saved to disk across restarts, plus the region-tracking system toggle.
persistent_data.yml decides which mob-tracking flags mcMMO saves to disk (persistent)
versus keeps in memory (transient), and whether the region system that tracks
player-placed blocks is enabled.
Persistence has a real performance cost: every saved flag means more disk work on chunk
unload, and Minecraft can build up tens of thousands of entities. Only enable flags while
watching your server's TPS. COTW_SUMMONED_MOB is the safe exception and stays on by
default.
Leave mcMMO_Region_System.Enabled on. It uses mcMMO's own fast file store (not NBT) and
blocks exploits like block dupes.
Default persistent_data.yml
Full default file shipped with mcMMO 2.2.054:
# This config allows servers to change which data is persistent and which data isn't
# For 10 years mcMMO had transient data (temporary) for a lot of things and recently in October 2020 I added the option to have things be persistent (saved to disk and permanently remembered)
# However, this is Minecraft, and Minecraft has a lot of entities, and when you start to make data persistent there is a performance cost associated with that
# Any option you turn on, is another thing your disk has to save when a chunk is being unloaded with that entity inside of it, Minecraft can quickly build up tens of thousands of entities so keep this in mind.
#
# I am considering alternative to using Spigots NBT API to avoid this performance cost, but the code for those will take some time to write and test, for now it is not recommended
# to turn any of these settings on without monitoring the TPS of your server afterwards. With the exception of the COTW setting which will probably have almost no performance impact if left on.
Persistent_Data:
Mobs:
Flags:
# By default mcMMO gives 0 XP for this type of mob, adjust in experience.yml
MOB_SPAWNER_MOB:
Saved_To_Disk: false
# By default mcMMO gives 0 XP for this type of mob, adjust in experience.yml
EGG_MOB:
Saved_To_Disk: false
# By default mcMMO gives 0 XP for this type of mob, adjust in experience.yml
NETHER_PORTAL_MOB:
Saved_To_Disk: false
# These mobs have low impact on performance and thus it is recommended you leave this on true
COTW_SUMMONED_MOB:
Saved_To_Disk: true
# By default mcMMO gives normal XP for player bred mobs, adjust in experience.yml
PLAYER_BRED_MOB:
Saved_To_Disk: false
# By default mcMMO gives 0 XP for this type of mob, due to an exploit in Minecraft you can spawn 1000 endermen in seconds using this trick.
# Adjust in experience.yml under the section labeled exploit fix
EXPLOITED_ENDERMEN:
Saved_To_Disk: false
# By default mcMMO gives 0 XP for this type of mob, not adjustable currently
PLAYER_TAMED_MOB:
Saved_To_Disk: false
# When players put down a block we track it, the system used to track player blocks is super efficient and has been coded extremely well
# It is never recommended to turn this off as it allows exploits such as player dupes etc
# We use our own file system for this outside of NBT which has been programmed to be lightning fast
mcMMO_Region_System:
Enabled: true