CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

Running in parallel on multiple nodes

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 18, 2012, 00:33
Default Running in parallel on multiple nodes
  #1
Member
 
Kalyan
Join Date: Oct 2011
Location: Columbus, Ohio
Posts: 53
Blog Entries: 1
Rep Power: 14
kalyangoparaju is on a distinguished road
Friends,

I was trying to run a case by using resources of 2 computers by using the following command.

mpirun --hostfile <machines> -np <nprocs> snappyHexMesh -parallel

When I script without the hostfile on 1 node with 8 processors, I don't get any errors but when I run the same script on 2 nodes using the machines names in the machines hostfile, I get an error saying

cannot find points in directory polymesh from 0 down to constant.

I tried checking if the constant directory had the polymesh directory and the points file in it and apparently, it does.

Can someone please help me. Where is it that I am going wrong?

regards,
Kalyan Goparaju
kalyangoparaju is offline   Reply With Quote

Old   January 18, 2012, 05:01
Default
  #2
Senior Member
 
BastiL
Join Date: Mar 2009
Posts: 530
Rep Power: 20
bastil is on a distinguished road
Hi,

you need to decompse your model in order to run in parallel. Run decomposePar in order to do this.

Regards Bastian
bastil is offline   Reply With Quote

Old   January 18, 2012, 10:22
Default
  #3
Member
 
Kalyan
Join Date: Oct 2011
Location: Columbus, Ohio
Posts: 53
Blog Entries: 1
Rep Power: 14
kalyangoparaju is on a distinguished road
Bastil,

I did do that. The following are the steps I followed.

1. blockMesh
2. decomposePar
3. mpirun --hostfile machines -np <nprocs> snappyHexMesh -parallel

The problem what I mentioned is when I do the third step.

Kalyan
kalyangoparaju is offline   Reply With Quote

Old   January 18, 2012, 11:41
Default
  #4
Senior Member
 
Elvis
Join Date: Mar 2009
Location: Sindelfingen, Germany
Posts: 620
Blog Entries: 6
Rep Power: 24
elvis will become famous soon enough
Hi,

do you have the files for the "simulation calculation" on both machines?
And do you have the same filesystem structure on both machines?
elvis is offline   Reply With Quote

Old   January 18, 2012, 12:13
Default
  #5
Member
 
Kalyan
Join Date: Oct 2011
Location: Columbus, Ohio
Posts: 53
Blog Entries: 1
Rep Power: 14
kalyangoparaju is on a distinguished road
Elvis,

As I understand, using MPI with machine files doesn't require us to have the working folder in both the system.

To answer your question, no I don't have the file in the slave nodes. But I will give it a shot now and see if it works.

Kalyan

Update - Elvis, I did put the folder in both the nodes and tried running. I get the same error
kalyangoparaju is offline   Reply With Quote

Old   January 18, 2012, 12:36
Default
  #6
Senior Member
 
Olivier
Join Date: Jun 2009
Location: France, grenoble
Posts: 272
Rep Power: 17
olivierG is on a distinguished road
hello,

In fact you need to have the working folder in both system (usually via nfs shared file system).

And you also need that snappyHexMesh can work on both system (so same as the working folder, you need openfoam on nfs, or install openfoam on the same dir on each machine).

You aslo need to source your bashrc on each node. On way to do this is to use foamExec.

And take a look at ssh access with shared key (doesn't need a password for each node).

regards,
olivier
olivierG is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
problem of running parallel Fluent on linux cluster ivanbuz FLUENT 15 September 23, 2017 20:12
running OpenFoam in parallel vishwa OpenFOAM Running, Solving & CFD 22 August 2, 2015 09:53
multiple parallel jobs on one machine joeybernard CFX 0 December 16, 2010 11:10
Running dieselFoam in parallel. Palminchi OpenFOAM 0 February 17, 2010 05:00
Minimum number of nodes to run CFX in parallel Rui CFX 3 April 11, 2005 21:46


All times are GMT -4. The time now is 05:19.