1 gb data rates across a 40 gb connection WHY?

[Toddb]

Hi

Newbi here so please be nice.

I'm using a Cisco 3132 switch.  I have 2 40 gb connections but only getting 1 gb transfer rates

According to linux networking app it shows 40000 mb/s  connection.

According to Cisco 3132 it also shows the 2 ports at 40 gb/s

But when benchmarking using iperf or transferring large files (100 gb in size)   I only see about a 1 gb/s transfer rate

Any suggestions?

[balaji.bandi]

cisco 3132  - not that it has built in tools , you can host guest shell again that has some limitation.

what i can suggest is any http or sftp and other side use wget multi instance see you can reach 40GB. 

Hope they are back to back connection right ? MTU 1500 bytes - also try jumbo frames.

z640 wkst  <--> mellanox 3 pro   - Hope this card support jumbo frames ?

[Toddb]

well this is bizarre,  after an extended power outage and eventual reboot i'm seeing much better transfer rates:

[ID] Interval Transfer Bitrate Retr
[ 5] 0.00-30.00 sec 16.4 GBytes 4.69 Gbits/sec 0 sender
[ 5] 0.00-30.04 sec 16.4 GBytes 4.68 Gbits/sec receiver
[ 7] 0.00-30.00 sec 16.4 GBytes 4.69 Gbits/sec 0 sender
[ 7] 0.00-30.04 sec 16.4 GBytes 4.68 Gbits/sec receiver
[ 9] 0.00-30.00 sec 16.4 GBytes 4.69 Gbits/sec 1 sender
[ 9] 0.00-30.04 sec 16.4 GBytes 4.68 Gbits/sec receiver
[ 11] 0.00-30.00 sec 16.4 GBytes 4.69 Gbits/sec 0 sender
[ 11] 0.00-30.04 sec 16.4 GBytes 4.68 Gbits/sec receiver
[SUM] 0.00-30.00 sec 65.6 GBytes 18.8 Gbits/sec 1 sender
[SUM] 0.00-30.04 sec 65.5 GBytes 18.7 Gbits/sec receiver

[Joseph W. Doherty]

So, hosts were rebooted?  Is so, if you had made some host configuration changes, they may have needed a reboot to be applied.

[Toddb]

they were rebooted. No ups this time battery had failed.  No changes were made.  Odd that problem corrected itself.

I did enable jumbo frames after the test just because I could. 

[jamesbos96602]

I WORK AT REFINERY SEEN THAT COMPUTERS ON SOME FLOORS WAS WORKING AT HAFE THE SPEED,   REASON FOR THIS WELL LETS SAY THE NETWORK ADMIN AND I HAD FEW PROBEMS IN THAT I NEW WHAT WAS GOING ON WITH THE NETWORK HE DID NOT,  I FOUND SOMETHING FIX IT I SEE YOUR PORTS SET AUTO  SET EVERY THING TO SPEED AND FULL DUPLX   SOME ODD REASON SWICHS CANT CONNET AT HIGHEST SPEED SO THEY CONNECT AT SPEED THAT WORKS ,   LOT THINGS CAN CUASE THIS MORE I COUNT, WIFI FOR ONE AND USEING UNSHEALDED CABLES,  CAN CAUSE THIS PROBEM,  CABLES THEM SELFS BE A PROBEMS IF NONE THEM WILL CONNECT TO ANY SWICH AT FULL SPEED, THIS BE PROBEM WITH FIRMWARE, OR SOFTWARE,  I CANT COUNT HOW MANY THINGS CAN CUASE THIS, SO START AT MOST SIMPLE GO FROM THERE