Using iPerf for Testing vSAN Network Performance
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Using iPerf for Testing vSAN Network Performance

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Article ID: 326526

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Updated On: 11-25-2024

Products

VMware vSAN

Issue/Introduction

Symptoms:

vSAN strongly depends on the underlying Network Performance to produce acceptable overall performance values.
For troubleshooting purposes one may have to measure the Network Performance of the VSAN Network.
The steps in Resolution below will explain how to do it, with the built-in tool available on ESXi.

Environment

VMware vSAN 7.x
VMware vSAN8.x

Resolution

  • Step 1: Start iPerf in Server Mode on one host
        On an esxi host enter the following to change to the working directory for Iperf.

        1. cd /usr/lib/vmware/vsan/bin

        • Looking in this folder you may see multiple copies of the iperf application. Either way there seems to be a permissions issue of some form with running this command directly so make a copy of the iperf program by running the following command

        • cp /usr/lib/vmware/vsan/bin/iperf /usr/lib/vmware/vsan/bin/iperf.copy2
  • Step 2: Disable the ESXi Firewall on all hosts
         esxcli network firewall set --enabled false
 
  • Step 3: Start iPerf in Server Mode on one host
         [root@esx03-nla1:/usr/lib/vmware/vsan/bin] ./iperf.copy -s -B 193.xx.xx.xx -i 1
       ------------------------------------------------------------
      Server listening on TCP port 5001
      Binding to local address 193.xx.xx.xx
      TCP window size: 64.0 KByte (default)
      ------------------------------------------------------------
      [ 4] local 193.xx.xx.xx port 5001 connected with 193.xx.xx.xx port 12677
      [ ID] Interval Transfer Bandwidth
      [ 4] 0.0- 1.0 sec 866 MBytes 7.27 Gbits/sec
      [ 4] 1.0- 2.0 sec 937 MBytes 7.86 Gbits/sec
      [ 4] 2.0- 3.0 sec 921 MBytes 7.72 Gbits/sec
      [ 4] 3.0- 4.0 sec 930 MBytes 7.80 Gbits/sec
      [ 4] 4.0- 5.0 sec 940 MBytes 7.88 Gbits/sec
      [ 4] 5.0- 6.0 sec 933 MBytes 7.83 Gbits/sec
      [ 4] 6.0- 7.0 sec 952 MBytes 7.98 Gbits/sec
      [ 4] 7.0- 8.0 sec 936 MBytes 7.85 Gbits/sec
      [ 4] 8.0- 9.0 sec 936 MBytes 7.85 Gbits/sec
      [ 4] 9.0-10.0 sec 879 MBytes 7.38 Gbits/sec
      [ 4] 0.0-10.0 sec 9.01 GBytes 7.74 Gbits/sec

 

  • Step 4: Run iPerf in Client mode connected to Server Node
        [root@esx04-nla1:/usr/lib/vmware/vsan/bin] ./iperf.copy -c 193.xx.xx.xx -fM
      ------------------------------------------------------------
      Client connecting to 193.xx.xx.xx, TCP port 5001
      TCP window size: 0.03 MByte (default)
      ------------------------------------------------------------
      [ 3] local 193.xx.xx.xx port 12677 connected with 193.xx.xx.xx port 5001
      [ ID] Interval Transfer Bandwidth
      [ 3] 0.0-10.0 sec 9230 MBytes 923 MBytes/sec
      [root@esx04-nla1:/usr/lib/vmware/vsan/bin]

 

  • Step 5: Re-enable the ESXi Firewall on all hosts

        esxcli network firewall set --enabled true