Really odd server lag randomly appearing

Discussion in 'Bukkit Help' started by xNaXDy, Sep 14, 2013.

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    xNaXDy

    This is the situation:

    I have 4 servers in total and the fourth one lags. Server 2 and 3 aren't really interesting, so we'll just leave them out. I'm running all servers on the same machine, a Linux server with an Intel i9 quad core processor (8 logical cores) and 42 GB ram. Each server has 8 GB ram assigned, because more are not needed (doing an Essentials /lag check shows that I have about 4GB free even when the server is full). My problem is that I recently installed that new server 4, but entities seem to cause a HUGE amount of lag on there.

    The server has custom biomes using TerrainControl, so I thought that may be the issue, so I let the world pre-generate using world border and I then disabled TerrainControl, but it was no use. I also disabled ALL of the plugins and reverted all the configuration files to their original state, but it was no use either.

    What's happening is that if about 100 entities (which were spawned naturally) are in the visible field (like when they can move and are being updated) the server starts to lag a LOT. I tried to replicate the issue on server 1 by manually spawning about 1,000 entities in the visual field (using Essentials /spawnmob command), but it didn't drop below 20 TPS, all that happened was a huge FPS lag, but the server was fine.

    My question would be: Why does server 4 lag and server 1 doesn't? They are running on the same machine with basically the exact same preferences. Does it have something to do with entities being spawned naturally and manually? Or is the cause something completely different?

    Please help me, I am very desperate.
     
  2. Offline

    ShadowDog007

    xNaXDy
    There is no such thing as an 'Intel i9' CPU.

    Do you have timings from server 4?

    Do both servers use TerrainControl?
    Depending on your settings for that, if you have a lot of caves, you can get massive buildups of mobs within those caves, even though you can't see them they can still take up CPU time.

    You could try reducing the number of mobs with MobManager. (Will remove all mobs too far above/below the player.)

    You could also try reducing minecrafts mobs per chunk limits. Although that can reduce the number of mobs you see (Unless you use MobManager ;) )
     
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    xNaXDy

    ShadowDog007

    I meant the Intel i7 CPU of course <_<

    No, server 1 doesn't use TerrainControl. There aren't any caves, since I don't want that for server 4. Also, the issue can't be TerrainControl, since it was still happening after removing all plugins. The TerrainControl world was still there, but the lag even happened in the ocean.

    I don't want to remove mobs, since it's very important for the server that they stay there (especially zombies), so unfortunately that's not an option. But like I said, server 1 is capable of updating over 1,000 entities without having even a little lag, why can't server 4 do that?
     
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    ShadowDog007

    xNaXDy

    So do you have timings?
     
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    xNaXDy

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    ShadowDog007

    xNaXDy

    In bukkit.yml, check plugin-profiling is set to true.

    Type '/timings on'

    A while later type '/timings merged'

    Upload the contents of 'timings/timings.txt' to http://paste.ubuntu.com/

    Then go to http://aikar.co/timings.php, and enter the ID of the paste. Post the link here.
     
  7. Offline

    xNaXDy

    ShadowDog007
    http://aikar.co/timings.php?url=6110242

    I let the timings run for about 4 minutes and had a survival-mode player stay on a tower and randomly knock zombies. The average TPS was about 8.

    Note: Plugins with a "Dom" prefix are custom plugins made by me, so I have full control over them.
     
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    Necrodoom

    Update plugins to versions that are not ancient (Essentials especially - you are using a build for bukkit for MC 1.3.2...) and run timings again.
     
  9. Offline

    xNaXDy

    http://aikar.co/timings.php?url=6110528

    Updated the plugins, server still lags. Timings were made exactly the same way like before.

    Edit: Server 4 starts to lag with about 50 entities (which is REALLY odd), while server 1 is capable of holding 1,000 and more (even when they are being updated, like near a player), even though server 1 still has "anchient" plugins.

    Important Update: I finally found the source of the lag!

    It seems to be an issue regarding pathfinding. If my dummy player is at an unreachable point (e.g. in a house or on top of a tower) it causes lag. However if the dummy player is at the floor, or at another location where the zombies can reach them, it does not cause any lag whatsoever (no matter how many zombies are spawned).

    The real question would now be: How to disable zombies trying to get to an unreachable location?
    or
    How to determine whether the target of the zombies is reachable?

    EDIT by Moderator: merged posts, please use the edit button instead of double posting.
     
    Last edited by a moderator: Jun 4, 2016
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    Sam991

    why u got 4 servers anyway
     
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