PSX Server Crashing

[CaptainSmurf]

Hi All. Any ideas what could cause the PSX server to crash/freeze.

Been happening quite a bit at our sim, boot up the sim in the morning. Once all loaded come to do a takeoff off or start a landing and the server instance crashes. Neither the layout or instructor panel can be selected. I have to Ctrl-Alt-Del to close it and restart. Happened 4 times this morning. Also have to reboot the client PCs as they no longer connect once it's been rebooted. Engine sounds are still there when it crashes and none of the axis work.

PSX server is minimised as it's on the same PC as the Xplane graphics

Hoping it's something simple.

Many Thanks

Phil

[Jeroen Hoppenbrouwers]

Crash is not the same as freeze; there are clear differences.

A crash is when the program ends (or is ended by the OS) and all server displays dissolve and the task bar icon disappears.

A freeze is when everything remains as it is, but nothing responds any more.

The most likely (but not the only possible) cause of a freeze is that one of the add-ons stopped accepting the data that PSX tried to send it. PSX relies on the OS to buffer outgoing data but those buffers are finite. Once full, the OS will stop (freeze) PSX hard because TCP links guarantee to not lose data.

I would suggest, on the next freeze, to start killing your clients one by one to see which one may hang up PSX.

Most PSX Routers also guard against this effect by adding more buffering themselves, instead of requiring (just) PSX to buffer output. Using a Router as extra monitor/guard device in a larger sim setup is pretty common.


Hoppie

[CaptainSmurf]

Thanks Hoppie. It is a freeze then rather than a crash.

All the instances are connected via a switch.

By killing each instance will that unfreeze the main PSX server so I'll know which one is causing the issue?

[Jeroen Hoppenbrouwers]

An Ethernet switch does not matter. The problem is at the TCP level, switches stop at the IP level. You probably even see still all LEDs blinking.

Yes, once you kill the offending client (assuming this IS the problem), PSX should immediately unfreeze.

[CaptainSmurf]

Thanks Hoppie. I'm back in the sim tomorrow morning so will give your advise a try.

If I find the client that is causing the freeze how do I go about stopping it causing the freeze going forward?

Thanks

[Jeroen Hoppenbrouwers]

That probably requires a software modification of that client. There is very little that you, as the user, can do about it. Finding exactly when that client stops accepting data (which may be several minutes before the buffer fills up) is probably the best you can do.


Hoppie

[Roddez]

Sounds like something on the network is spamming PSX with data, causing it to appear frozen and unresponsive.  We have seen this in the past in some installations.

Rod.

[Hardy Heinlin]

There was an add-on – don't remember the name – that stopped reading when it lost the desktop focus. Maybe it was a remote CDU add-on for an iPad, but I'm not sure.


|-|ardy

[macroflight]

The PSX CDU Remote iPad app has been reported to cause freezes (see e.g https://aerowinx.com/board/index.php/topic,5897.msg63741.html). I use it all the time, and had exactly one freeze in three years... but others report far worse problems. It might be due to switching between apps (I only use that old iPad for the remote CDU) - if the app runs in the background, IOS might not let it run often enough and it can then not keep up with the data stream from PSX, causing the network buffer to fill up and the PSX main server to freeze.

If the problem is not a PSX instance or addon that freezes up but instead something that spams the PSX main server with too much traffic, you might be able to use (in lieu of a traffic-logging PSX router which is probably more work to set up) Wireshark or some similar tool to monitor network traffic to port 10747 on the computer where the PSX main server runs. If there is so much traffic from a single client that it bothers PSX, it ought to be obvious from the network traffic who is responsible.

[CaptainSmurf]

Thanks for the info Macroflight. We don't use the PSX CDU Remote app as we have a real CDU in the pedestal.