Fluent 2021 R1 running on a linux server has issues with Intel MPI 2018

- November 23, 2021 at 5:44 pm
  
  BjornKierulf
  Subscriber
  
  I am trying to run cases in Fluent on a remote linux server via GUI. When fluent loads it gives the following message in the text interface:
  
  Host spawning Node 0 on machine "d0147" (unix).
  /shared/centos7/ansys/2021-R1/ansys_inc/v211/fluent/fluent21.1.0/bin/fluent -r21.1.0 3ddp -flux -node -alnamd64 -t32 -pinfiniband -mpi=intel -ssh -mport 10.99.101.147:10.99.101.147:43661:0
  
  -------------------------------------------------------------------------
  Intel MPI 2018 may not work due to DAPL deprecation in Mellanox OFED 5.1
  * Use -pib.ofed in such case.
  -------------------------------------------------------------------------
  
  Has anyone encountered this error before, or does anyone know what could be causing this? Additionally, does anyone know how or where I would specify the -pib.ofed tag? Since I am using a GUI I don't type the command to launch Fluent.
  
  Thanks,
  Bjorn Kierulf
- November 29, 2021 at 2:50 pm
  
  Hunter Wang
  Ansys Employee
  
  Check latency and bandwidth in Fluent GUI > Parallel, if latency values are lower than 3 and bandwidth values are higher than 3GB, IB with DAPL should still work.
  To force to used OFED (ofa farbrics for Intel MPI 2018), try to add -pib.ofed when launching Fluent launcher, also add -mpiopt="-genv I_MPI_DEBUG=2" as below to print Intel MPI debug info.
  /shared/centos7/ansys/2021-R1/ansys_inc/v211/fluent/bin/fluent -pib.ofed -mpiopt="-genv I_MPI_DEBUG 2"
  in Fluent launcher GUI > Parallel Settings > Interconnects, it should show ib.ofed, also in Fluent Console (after it's launched), it should print Intel MPI fabrics info:
  ...
  MPI startup(): shm and ofa data transfer modes
  ...
- April 9, 2023 at 6:10 am
  
  kevin1986
  Subscriber
  
  > bandwidth values are higher than 3GB
  In windows, I found 2021/2022/2023 bandwidth is much slower than 3GB. Please check the details here: /forum/forums/topic/new-version-fluent-is-slower-than-2020r2/
  We were stuck here for more than a year. We dont know why..
- May 15, 2023 at 7:11 am
  
  coalition strengthen
  Subscriber
  
  IB with DAPL should continue to function if the latency value is less than 3 and the bandwidth value is more than 3GB. To output Intel MPI debug data, use the -mpiopt="-genv I_MPI_DEBUG=2" and -pib.ofed options with the Fluent launcher to force the usage of OFED (ofa farbrics for Intel MPI 2018).
  dordle