Problem with ConnectX-2 Card! transfer-rate not simetrical!

Infrastructure & Networking Software And Drivers WinOF Driver
1

Hi,

I have 2 computers both with a mellanox ConnectX-2 Card and Windows 8.1.1 x64 updated. I use OFED 4.95 driver and I have the latest firmware for both cards. I use arista transceivers of 10GB.

Computer A:

AMD FX-8350 with 8GB of RAM and PCI-E x16. 4 HHD in RAID0 with a 680MB/s of sequential speed of read and write (Hitachi Deskstar 7K4000).

Computer B:

Intel G1840 with 2GB of RAM and PCI-E x16. 4 HHD in RAID0 with a 550MB/s of sequential speed of read and write (WD Green).

I share one folder in computer A and one folder in computer B. The folder are in RAID0 volume, obviously. The windows system is in another hard-drive, not in the RAID0.

My problem is:

When I copy one file of computer B to computer A I get 530MB/s of transfer-rate. This is right.

But When I copy one file of computer A to computer B I get only 270MB/s of transfer-rate. This is wrong. Why not 500MB/s at least?

I don’t understand! Is it a problem of the computer hardware? or is it a problem of configuration mellanox card?

I tried the same in another Computer C:

Computer C:

AMD Kabini A4-5000 with 8GB of RAM and PCI-E x4. SSD with 550MB/s of sequential speed of read and write (Samsung 850EVO 500GB)

So:

When I copy one file of computer C to computer A I get 530MB/s of transfer-rate. This is right.

But When I copy one file of computer A to computer C I get only 120MB/s of transfer-rate. This is wrong. Why not 500MB/s at least?

I can’t try it with Computer B and C. Now I don’t have the Computer C. I have changed the Kabini computer for an intel computer only for this problem

Any solution for this? my head is burning haha!!

Thank you masters!!

2

Hi Enric,

Beside the fact that your test servers are not alike and it is probably not going to ever be the same, measuring performance using a file transfer is not the right way of finding the root cause.

I do understand where you are trying to get but you need to make sure you test your performance properly.

First thing first: the file transfer is done over network, so we will need to test the network only prior. Next, you can test the rest of the E2E elements (test the local server’s performance, RAID performance, etc).

for only testing the network’s performance i recommend on using known benchmarks like iperf - run it in a client-server mode and run at list 8 threads so you are utilizing your server resources properly.

Other then that, you can look into the server performance tuning guide: http://www.mellanox.com/related-docs/prod_software/Performance_Tuning_Guide_for_Mellanox_Network_Adapters.pdf http://www.mellanox.com/related-docs/prod_software/Performance_Tuning_Guide_for_Mellanox_Network_Adapters.pdf

hope it helps…