BZFS unstable on Ubuntu server

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Grans Remedy
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BZFS unstable on Ubuntu server

Post by Grans Remedy » Wed Dec 16, 2009 4:51 am

Howdy,
I've compiled BZFS (2.0.13) on an Ubuntu server (Linux VPS).

At certain times all players start getting lag warnings because their lag is showing as very high - often over 1000ms and/or they go NR.

However, when this happens, those same players can ping the server from a command prompt, and get response times that are normal. For example ping times outside of BZFlag around 60ms, lagstats show the player having lag of 1000ms with high jitter and packet loss.

I have been collecting ping times and screen grabs of this, but am unsure what to do now.

I have tried recompiling, but that made no difference.

FWIW: ./configure --disable-client --enable-shared
No errors

Any ideas anyone?
Thanks
Grans
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blast
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Re: BZFS unstable on Ubuntu server

Post by blast » Wed Dec 16, 2009 12:40 pm

Might just be a problem with your VPS. ICMP (ping), while still part of the IP protocol suite, is different than TCP and UDP and might get treated/handled differently.
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Re: BZFS unstable on Ubuntu server

Post by joevano » Wed Dec 16, 2009 2:31 pm

Most of the public servers run 2.0.13 . While it could technically be called an "unstable" version based on the numbering convention it is pretty rock solid and has been run in production environments for quite some time. I would have to agree with blast that a likely cause is your VPS. I know that there have been several attempts to run public servers on VPS servers and that they have had mixed success. Some work just fine and others have mysterious unexplained issues that disappear when moved to a different provider or a dedicated server.
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Re: BZFS unstable on Ubuntu server

Post by Grans Remedy » Thu Dec 17, 2009 5:21 am

Thanks for your feedback.

I'm fairly confident its not the server (VPS), because I've had the hosting company look into this too. They have confirmed that during the time players are getting very high lag warns the server is not under any stress: Low CPU time, little disk I/O, limited network traffic. They are at a loss as to why this app (BZFS) is behaving so poorly.

Generally I find that if I ssh into the server, kill the processes and restart them, then we're good to go - for a while. But that's annoying, especially when the server is used for offi matches.

I was wondering if there is some known issue with BZFS 2.0.13 on Ubuntu LTS 8.04 (Hardy Heron) maybe?

Oddly, I had a similar issue with this version of BZFS on another VPS (running CentOS) which is why I jumped ship to this new hosting provider and VPS as in this post http://my.bzflag.org/bb/viewtopic.php?f=103&t=15390

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Re: BZFS unstable on Ubuntu server

Post by blast » Thu Dec 17, 2009 1:40 pm

I run 2.0.13 (latest code) on Debian Etch, and haven't had any issues where very player suddenly had high lag. I did have one issue recently where my lag jumped up a little bit (about 20 to 40 ms) and I suddenly had packet loss for about 15 minutes - while when I joined another client from the same computer, I didn't have any packet loss. But I'm more inclined to think that was just some random issue with the specific connection, not with bzfs.
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