CFX error: "enforce system memory limit"

johny0688 · April 25, 2018, 07:18

Hi All,
I got error about memory limit.
+--------------------------------------------------------------------+
| ERROR #333100220 has occurred in subroutine Out_MemPar. |
| Message: |
| |
| The allocated memory exceeds the system memory on 1 host(s). |
| |
| The logical expert parameter "enforce system memory limit" |
| controls whether this is a fatal error. |
| |
| The current setting is: fatal |
| |
| Allocating more than the system memory may result in slow or |
| unreliable operation and is not recommended. |
+--------------------------------------------------------------------+
It is obvious because my workstation doesn't have enough RAM (currently 128Gb). However I need to force CFX to use swap memory. I tried to find expert parameters enforce system memory limit but I couldn’t. Can someone tell me where to change expert parameters so that the error will not be fatal and allowed CFX to work in swap?

The problem is urgent so I ask you for quick answer.
Thanks in advance

ghorrocks · April 25, 2018, 08:07

CFX does not handle using swap space. That is handled by the OS. So check your OS settings to ensure you have adequate swap space allocated. But it is a bad idea to use swap for a CFD simulation - it will slow down to the extent that it will converge at a glacial pace.

You need to install more memory, more parallel nodes or make the simulation smaller.

Gert-Jan · April 25, 2018, 08:14

Or ask someone else to do your calculation. See the Freelance forum.

ghorrocks · April 25, 2018, 08:18

Or buy some time on a cloud computer like AWS which you can scale to as big as you like.

johny0688 · April 25, 2018, 08:38

Thanks for answers,
Actually it is not possible to give calculation outside. Also I can’t install more memory since I9 architecture can’t handle with higher amount of memory.
I have cut out piece of my model to reduce mesh and the calculation runs with about 125Gb consumption

The cut part doesn’t contain much elements so I guess it should be automatically put into swap. But it isn’t. That why I thing that there is some expert parameters which is responsible for allocating memory in swap.

ghorrocks · April 25, 2018, 09:04

If your cut down model requires 125GB then you REALLY need to be using distributed parallel. A model that big will run well shared across a few nodes.

DaveD! · March 24, 2021, 14:05

The error occurs, if the solver tries to allocate more memory than your system has. Allocation means, that the solver estimates how much RAM it will need during solution. However, it does not mean, that it actually needs it.

So, one thing that helped me was to set the Solver's Memory Allocation Factor to a value smaller than 1, e.g. 0.8. Other settings like "Large Problem" partitioning were not necessary in my case.

Hope that helps.

Regards, DaveD!

April 25, 2018, 07:18	CFX error: "enforce system memory limit"	#1
johny0688 Member Jan Surwiło Join Date: Feb 2017 Posts: 31 Rep Power: 9	Hi All, I got error about memory limit. +--------------------------------------------------------------------+ \| ERROR #333100220 has occurred in subroutine Out_MemPar. \| \| Message: \| \| \| \| The allocated memory exceeds the system memory on 1 host(s). \| \| \| \| The logical expert parameter "enforce system memory limit" \| \| controls whether this is a fatal error. \| \| \| \| The current setting is: fatal \| \| \| \| Allocating more than the system memory may result in slow or \| \| unreliable operation and is not recommended. \| +--------------------------------------------------------------------+ It is obvious because my workstation doesn't have enough RAM (currently 128Gb). However I need to force CFX to use swap memory. I tried to find expert parameters enforce system memory limit but I couldn’t. Can someone tell me where to change expert parameters so that the error will not be fatal and allowed CFX to work in swap? The problem is urgent so I ask you for quick answer. Thanks in advance

April 25, 2018, 08:07		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	CFX does not handle using swap space. That is handled by the OS. So check your OS settings to ensure you have adequate swap space allocated. But it is a bad idea to use swap for a CFD simulation - it will slow down to the extent that it will converge at a glacial pace. You need to install more memory, more parallel nodes or make the simulation smaller. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

April 25, 2018, 08:18		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Or buy some time on a cloud computer like AWS which you can scale to as big as you like. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

April 25, 2018, 09:04		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	If your cut down model requires 125GB then you REALLY need to be using distributed parallel. A model that big will run well shared across a few nodes. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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April 25, 2018, 08:14		#3
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,928 Rep Power: 28	Or ask someone else to do your calculation. See the Freelance forum.

April 25, 2018, 08:38		#5
johny0688 Member Jan Surwiło Join Date: Feb 2017 Posts: 31 Rep Power: 9	Thanks for answers, Actually it is not possible to give calculation outside. Also I can’t install more memory since I9 architecture can’t handle with higher amount of memory. I have cut out piece of my model to reduce mesh and the calculation runs with about 125Gb consumption The cut part doesn’t contain much elements so I guess it should be automatically put into swap. But it isn’t. That why I thing that there is some expert parameters which is responsible for allocating memory in swap.

March 24, 2021, 14:05		#7
DaveD! New Member Join Date: Feb 2016 Posts: 21 Rep Power: 10	The error occurs, if the solver tries to allocate more memory than your system has. Allocation means, that the solver estimates how much RAM it will need during solution. However, it does not mean, that it actually needs it. So, one thing that helped me was to set the Solver's Memory Allocation Factor to a value smaller than 1, e.g. 0.8. Other settings like "Large Problem" partitioning were not necessary in my case. Hope that helps. Regards, DaveD!