MSA 2040 IP jumbo packet size with VMware ESXi 6.5 hosts

[Altoon]

Hello,

I have three ESXi 6.5 hosts connected through Cisco switches to a MSA 2040 using iSCSI.  Jumbo frames have been enabled in each device.  

MSA 2040 - Jumbo Frames enabled

Cisco  - jumbomtu 9000

ESXi - vmk's nic settings MTU 8900 (per https://www.stephenwagner.com/2016/11/05/hpe-msa-2040-jumbo-frames-and-mtu-configuration/)

When I perform a tcpdump-uw on the ESXi host the largest packet size I see is 4144. I would think I would see something in the 8000 range.   A vmkping -d -s 8872 command works successfully.  

Is 4144 the max tcp packet size I should expect?

Thank you,

Altoon

[SUBHAJIT KHANBARMAN_1]

As you said vmkping command worked successfully then there is no question of the capability of your setup to handle Jumbo frames.

Now question is exact trafiic flow and how to measure it and from that you are checking if it's hitting 8000 or not. In that case it's a question of using packet snif method.

May be better to use some third-party packet sniffer software inside one of the virtual machines on the vSwitch.

Hope this helps!
Regards
Subhajit

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