vSAN1

 View Only

  • 1.  vSAN: MTU check (ping with large packet size)

    Posted Mar 15, 2023 02:02 PM

    Hello all! 

    I have vSAN stretch cluster 12 nodes on 2 sites and Witness site. I wanted to do vSAN traffic separation, because we've got MTU errors
    "vSAN: MTU check (ping with large packet size)". 

    So I created new dist.port group on our 1500MTU adapters and added new vmkernel adapter to hosts and tagged the traffic "Witness"

    >> esxcli vsan network ip add -i vmkx -T=witness

    What did I got? 
    Traffic FROM ESXi Host TO Witness Host = OK = No more errors in skyline health 
    Traffic FROM Witness Host to ESXi Host = ERROR in skyline health

    I did everything like this: https://infrapcs.com/2021/02/04/vxrail-vsan-stretched-cluster-witness-traffic-separation-configuration/comment-page-1/

    BTW. I can ping from witnessHost to esxiHost and the other way around with NO errors.

    How to get rid of that errors, is this some bug or? i mean the traffic passes trough fine.

    Thank you in advanced!






  • 2.  RE: vSAN: MTU check (ping with large packet size)

    Posted Mar 16, 2023 08:02 AM

    I believe this is a known issue, you can just mute the error, it is being worked on by the team.



  • 3.  RE: vSAN: MTU check (ping with large packet size)

    Posted Mar 16, 2023 10:10 AM

    I mean, i checked now:
    - on ESXi hosts on physical ports (on the switch) the MTU is 9216
    - on Witness host on the physical (on the switch) the MTU is 1500


    BUT, on ALL (ESXi and Witness hosts) the vmkernel adapter is set to 1500.
    Is it possible that vcenter looks and physical port MTU set and ignores the vmkernel adapter setting?