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July 31, 2017, 07:59 |
OpenFoam stops when there is no internet
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#1 |
Member
Lenzo
Join Date: Feb 2014
Posts: 33
Rep Power: 12 |
Hello there,
my terminal process of openfoam stops after a minute since I unpluged the ethernet cable, and so, i left my computer without internet. So: I unplug, 1 minute or two and then the simulation stops. Anyone knows why this happens? How could I solve this problem? I would like to continue the simulation during the weekends without wondering if it is still running. I attach the picture if you want to see the last report that i see on the screen. Thank you very much!! |
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July 31, 2017, 09:39 |
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#2 |
Senior Member
Kevin van As
Join Date: Sep 2014
Location: TU Delft, The Netherlands
Posts: 252
Rep Power: 20 |
OpenFOAM does not need ethernet/internet connection.
Therefore, I assume that you are running OpenFOAM in a terminal which requires ethernet connection, because either (perhaps I forgot a possibility):
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August 1, 2017, 03:33 |
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#3 |
Member
Lenzo
Join Date: Feb 2014
Posts: 33
Rep Power: 12 |
Thank you Kevin!!
I have considered all the 3 options, but it is not any of them. My machine has a local log-in, and my ssh is definitelly local as well. So i don't have to reach it with ethernet, and i write and read also from this ssh local. It truly doesn't make any sense! So, today i have been testing different options. When I unplug the ethernet cable, after a while, it stops. But then, If I run again the case (while offline), apparently, i doesn't stop! So, for the moment I will just directly unplug it and use the nohub command. I will let you know if it results! Thanks |
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August 4, 2017, 04:54 |
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#4 |
Member
Lenzo
Join Date: Feb 2014
Posts: 33
Rep Power: 12 |
Let me report how is it going on.
As i explained, everytime I disconnect my ethernet cable, after a little while (can be 30 sec or 3 min) openFoam stops running simulations. Without error message, simply stops. But, once I am disconnected, if I reRun the case, it just continues, and it doesn't stop anymore... So, I can't understand why the deuce openFoam has to stop just because I disconnect ethernet, but, at least, i found out that if I rerun while disconnected, it just works fine. Thank you. If anyone might have an idea why it stops would be wonderful. I work with OpenFoam 4.1 (of openfoam foundation) |
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August 11, 2017, 03:37 |
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#5 |
Member
Lenzo
Join Date: Feb 2014
Posts: 33
Rep Power: 12 |
Hello there,
so let me update this problem. I have discovered that if I run the case without decompose it for parallel solution (so It means only using one CPU) and I disconnect the ethernet cable, it doesn't stop at all! It is only when it's working the parallel method. Thus, it means that the problem with the ethernet necessity is from the MPI tool. Someone can figure out why and how to solve it? Thank you! |
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April 4, 2018, 20:52 |
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#6 |
Senior Member
Gerhard Holzinger
Join Date: Feb 2012
Location: Austria
Posts: 339
Rep Power: 28 |
This behaviour has been reported to OpenFOAM's bug tracking, and has been closed as this behaviour is caused by MPI an not OpenFOAM.
I noticed similar behaviour on my laptop, which is connected to a fragile wireless. I was running local jobs with 2 processes. As the wireless network is fragile, the connection fails frequently. I noticed my parallel runs stopping without any error message whatsoever. After some searching on the interwebs, I found this thread and the bug report I linked. Thus, the solution to the original question: do not unplug your machine. I know, this really sounds like stupid advice. As with fragile wireless connections, I need to figure out a way to tell MPI to ignore any interconnections. Here is how to tell MPI not to use the wifi, which is named wlp3s0 on my system. This needs two statements, one for BTL and one for OOB. Disabling wifi only for BTL and omitting the statement for OOB, or vice versa, will not work. Code:
mpirun --mca oob_tcp_if_exclude wlp3s0 --mca btl_tcp_if_exclude wlp3s0 -np 2 myFoamSolver -parallel > foam.log & BTL: MPI point-to-point Byte Transfer Layer, used for MPI point-to-point messages on some types of networks OOB: Out of band messaging See this, and this questions. Last edited by GerhardHolzinger; April 4, 2018 at 21:42. Reason: expanded answer with how to tell mpi not to use wifi |
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