[2.1.1] Server lag causes chunks not to send to client (Condenser). [RESOLVED]

[ckxng]

Launcher/pack Version: technic-launcher-latest.jar v0.5.4.9; Tekkit (always rec.) 2.1.0/1.1

Operating System: Win 7 64-bit

Version of Java: 1.6.0_30-b12

Description of Problem:

The server appears to be having difficulty sending chunks to clients (myself and the other player on the server). Most of the time we get no chunks at all and wind up glitching in the air. Sometimes, we get chunks around our initial location, but as we walk... no chunks. I tried installing a mod (ChunkManager?) that provided a /chunkme command, and the server seems to have no problem sending individual chunks on demand with that plugin. The chunks appear immediately, no lag or anything, suggesting to me that it's not a performance issue. But I removed the plugin as soon as I finished that test... the last thing I need is another thing out there messing with chunks while I'm troubleshooting this. That plugin was removed and the server rebooted before these logs and screenshots were made.

The time I took the server log and the screenshot is one of the times that I actually got some chunks around my login position... which was fortunate because there's no point in just a blue glitchy screenshot. You already know what that looks like. I also included a few commands to show server performance. As you can see, there's plenty of RAM free CPU is not strained and the network has plenty of capacity. (Download speed is shown, but upload speed is fine as well... faster than my home network anyway, which is the real bottleneck - 5Mbit or so).

I've used this same server since shortly after the release of Tekkit 2.0 with no problems. We upgraded to 2.1.1 from 2.0 around the time that the client updated and everything seemed fine up until now. This chunk problem has been consistent for about 24 hours now.

We have one quarry, some cobble->EE farms, but it's all working not spewing items on the ground... everything seems fine if we can just get the chunks. Also, I seem to be able to ride minecarts straight through the unloaded chunks. As long as I don't get out of the cart, it all seems fine.

This is a OpenVZ server, and I know that performance probably isn't optimal... but I don't see any indications that point to performance, so I'm hesitant to blame OpenVZ. Disk access delays characteristic of shared environments are also probably not the issue; I tested running the world from a tmpfs and it had the same problem.

I've read all the stickies in this section and searching for chunk loading issues, both on this forum and Google, without finding any answers. I found a few similar reports, but none with a resolution.

I do have a 32-bit java installed, but I've been playing MC for over a year with 32-bit java and no problems. I have a few apps that have compatibility problems with the 64-bit java. Also, this doesn't look like a client issue since the server CAN send the chunks on-demand if I use that plugin. But if you really think that the java version might be the problem, I can try switching to 64-bit for troubleshooting purposes, but that's going to cause problems for me with other apps.

Error Messages: none.

Link to pastebin of log: http://pastebin.com/enxWfX9F

So I suppose my main question is: Are there any known issues that might cause the server to simply decide not to send any chunks or send them WAY slower than it should despite having RAM, CPU, and network bandwidth to spare?

Sorry for the long post, but I wanted to provide as much troubleshooting detail as possible. I appreciate your time if you actually decide to read this and respond, despite its length. Thanks!

EDIT: I forgot to mention, ping to the server is a pretty consistent 50-65ms.

EDIT2: Also, it seems that completely wiping the world and starting over fixes the problem... so I suppose the real question now is whether or not anybody knows what happened and what I might be able to do to recover my world, or keep it from happening again...

EDIT3: Updated subject to better indicate the issue (was: Server appears not to be sending chunks to client.) and that the issue is resolved.

[freakachu]

Re: Server appears not to be sending chunks to client.

most of the world corruption errors I have seen result in people crashing in affected chunks, or the server not loading the world at all. I can't recall ever seeing an issue like this in the admittedly short time I've been trolling this forum. I suppose one thing you could try is to log in with the messed up world, and teleport yourself somewhere far away. see if that loads and/or generates the chunks out there, away from the other stuff.

you could also load the world up in MCEdit and see if maybe someone did screw something up on accident and spew hella items all over the ground somewhere (maybe an engine blew up? who knows). might be able to fix it that way too.

[Sp0nge]

Re: Server appears not to be sending chunks to client.

U prob have a issue with someone using a wooden pipe on a condensor. If this isnt near /spawn, its fixable as long as you have some sort of rolbacktools that can rollback 30ish min from the time it first happend.

As long as whatever conflicted chunk isnt loaded, u wont crash, but asap u load it, well, boom, GL HF!

If you dont have the proper tools to search for the issue, u are kinda forced to restart the map. If dont wanna go check the map with an editor, and see if u cant find any collectors with a wooden pipe to the m ... (that could take some time?)

[freakachu]

Re: Server appears not to be sending chunks to client.

I really don't think it's a pipe+condenser issue. the OP's pretty clear that he's not crashing, just not receiving chunks from the server. it sounds like everyone can log in fine, they just can't do anything due to perpetually falling in the void from not getting any chunk updates.

[Sp0nge]

Re: Server appears not to be sending chunks to client.

I really don't think it's a pipe+condenser issue. the OP's pretty clear that he's not crashing, just not receiving chunks from the server. it sounds like everyone can log in fine, they just can't do anything due to perpetually falling in the void from not getting any chunk updates.

Wooden on condensor makes the server lag out, and wont crash the client untill a while. We had the same, i sometimes could walk/fly around forever and only see those blocks.

Also he never stated anything about other being able to log on.

Are you able to log off, and log on when this happends? If not, im 99% shure its the issue of wooden + condensor.

Edit: After rereading the OP, im 99,99% shure its that issue. Its due to how the server is overloaded, it DC ppl, but the real server itselfe dont crashes. You cant prevent this if dont dissable condensors, or u use time on a testserver etc that u got o remove the faulty items in Q.

[ckxng]

Re: Server appears not to be sending chunks to client.

Wooden on condensor makes the server lag out, and wont crash the client untill a while. We had the same, i sometimes could walk/fly around forever and only see those blocks.

Interesting. I had seen the posts about wooden pipe on condenser, which we weren't doing. BUT, we did have redpower pipes going to a condenser... and that installation was the most recent thing before the crazy chunk loading problems started. Maybe the redpower pipes do it as well, but aren't as popular so nobody's really noticed yet? I'll load up the old world, force that chunk to load, and go whack that condensor.

And we could both login, but the lack of chunks made it difficult to do anything. Also, making the server laggy (apparently without running up the CPU?) might make sense and perhaps by why sometimes we got chunks near our login location... and sometimes nothing at all.

I'll post back after testing.

EDIT: Completely fixed. When the issue was first reported by the other guy on the server, I rolled back to 15 minutes before the issue began. If I had rolled back a few hours instead (wiping out his renovation/condenser) then all would have been well.

Pneumatic Tube + Condenser = FAIL ... or perhaps at this rate just condensers in general.

Good to know.

[Sp0nge]

It seems related to any item trying to withdraw from the condensor. I totally forgot about the tubes, they act the same was as the pipes basicly :)