[14.22] Desync again

[Bastian]

Moving this to Bug Reports since a desync like this shouldn't be possible, level_with_tags...dat is identical, but level.dat shows differences --daniel34

Hey, its me again.

you helped me an my friends with the heavy desyncs we had. Maybe you can try it again.

Here is my Desync report.

We are 3 players and have several desync situations. https://drive.google.com/open?id=0B1c6m ... ThjRTloZGc

Farlandsmodpack is active

[daniel34]

I have to refer this to the devs, I don't know how that desync is even possible.

Comparing the whole reference-level and desynced-level folders the only files that are different are level.dat and script.dat. The level_with_tags_tick_35898284.dat file is completely identical, which makes no sense since the level.dat itself is different.

When compared it replaces bytes (flips bits) in pairs, specifically 9E <--> 9F, 26 <--> 27, 9A <--> 9B throughout the file.

Image

factorio-desync-switch.png

The script.dat shows the same issues, it flips bits in pairs 3 times.
Maybe it's a memory error on that client, or on the server?

[Bastian]

Dont know what memory problem you mean?

game runs perfect since 2 weeks. we dont did anything. But the desync would be more often.

i just thought about that the problem may could be that, 2 of us had a cable internet provider with ds-lite tunel on ipv6. Do you think this could be the problem?

[daniel34]

Dont know what memory problem you mean?

game runs perfect since 2 weeks. we dont did anything. But the desync would be more often.

i just thought about that the problem may could be that, 2 of us had a cable internet provider with ds-lite tunel on ipv6. Do you think this could be the problem?

No, it's not a network issue, it's also not caused by mods.

In my opinion it's either an issue in Factorio or one of your PCs (or the server) has faulty RAM. But as I said, I've never seen a desync report like that and only the devs can tell you what's the issue here.
I'm not working for Wube, nor do I have access to the source code or anything, but in my personal opinion (with experience in IT and having analyzed desyncs before) that's the cause.

[Bastian]

Ok, can you please show my report to one of the devs?

[Rseding91]

Unless you've got some way to reproduce it there's not much I can do.

There's a difference in the script.dat file which means it could be a bad mod and there's a difference in the level.dat vs the level with tags.dat which means it could be bad RAM.

[daniel34]

If you are the only client this happens to then run a memory test (http://www.memtest.org/) on your PC. If there are other clients with the desync then run the memory test on the server. If this is not feasible then switch the server or have one of the clients hosting the game (taking the original server out of the equation) and see if that desync still appears.

[Bastian]

Ok that is the situation. We are 3 Person and we dont use an official server. Everyone of us had the desync problem. If i host my friend number2 had desyncs if he host then had friend 3 desync and if number 3 is the host then i had the desync.

We all Made memory test with memtest and had 0 error or failures.

[Bastian]

i have added one desync report from one of my friends.

https://drive.google.com/open?id=0B1c6m ... FZFcEh6YTQ

[Rseding91]

If you're using customizable inserters in blueprints there's a known desync issue with that.

[Bastian]

Oh that could be the problem. We worked a lot with custom inserters in blueprints.

Now we finished this work and dont had a desync yesterday.