iPerf showing lower throughput
Applies to
- ONTAP 9.11.1P8
- iPerf
Issue
- While running an iPerf throughput test on the Cluster network, lower than expected performance was observed
- iPerf Output example showing the issue:
[root@Cluster ~]# iperf3 -c <Dest Address> -T s1 -V
s1: iperf 3.9
s1: s1: Linux sto-test-03 5.14.0-284.11.1.el9_2.x86_64 #1 SMP PREEMPT_DYNAMIC Tue May 9 05:49:00 EDT 2023 x86_64
Control connection MSS 8928
s1: Time: Wed, 06 Sep 2023 11:49:54 GMT
s1: Connecting to host <Destination> , port 5201
s1: Cookie:
s1: TCP MSS: 8928 (default)
s1: [ 5] local <Source System> port 54628 connected to <Destination> port 5201
s1: Starting Test: protocol: TCP, 1 streams, 131072 byte blocks, omitting 0 seconds, 10 second test, tos 0
s1: [ ID] Interval Transfer Bitrate Retr Cwnd
s1: [ 5] 0.00-1.00 sec 1005 MBytes 8.43 Gbits/sec 68 1.40 MBytes
s1: [ 5] 1.00-2.00 sec 1.01 GBytes 8.68 Gbits/sec 54 2.02 MBytes
s1: [ 5] 2.00-3.00 sec 602 MBytes 5.05 Gbits/sec 0 2.71 MBytes
s1: [ 5] 3.00-4.00 sec 530 MBytes 4.45 Gbits/sec 0 2.98 MBytes
s1: [ 5] 4.00-5.00 sec 394 MBytes 3.30 Gbits/sec 104 1.74 MBytes
s1: [ 5] 5.00-6.00 sec 239 MBytes 2.00 Gbits/sec 0 2.12 MBytes
s1: [ 5] 6.00-7.00 sec 2.50 MBytes 21.0 Mbits/sec 0 1.93 MBytes
s1: [ 5] 7.00-8.00 sec 756 MBytes 6.34 Gbits/sec 36 2.43 MBytes
s1: [ 5] 8.00-9.00 sec 3.75 MBytes 31.4 Mbits/sec 0 2.43 Mbytes
s1: [ 5] 9.00-10.00 sec 579 MBytes 4.86 Gbits/sec 61 1.83 MBytes
s1: - - - - - - - - - - - - - - - - - - - - - - - - -
s1: Test Complete. Summary Results:
s1: [ ID] Interval Transfer Bitrate Retr
s1: [ 5] 0.00-10.00 sec 5.03 GBytes 4.32 Gbits/sec 323 sender
s1: [ 5] 0.00-10.03 sec 5.03 GBytes 4.30 Gbits/sec receiver
s1: CPU Utilization: local/sender 5.4% (0.3%u/5.1%s), remote/receiver 11.7% (0.1%u/11.7%s)
s1: snd_tcp_congestion cubic
s1: rcv_tcp_congestion cubic
s1:
s1: iperf Done.