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January 25th, 2023 00:00
MX840C giving me less than 25G
Hello geeks,
I have an environment were my MX840C blades plug directly in a chassis, these chassis are interconnected (converged infrastructure)
each Chassis has 4 - 6 blades. having ESXI 7.2 as the OS. each NIC in the blade is capable of offering 25G. at the vmware level i did NIC Teaming.
HOWEVER ON Using iperf to test two hosts speeds, i get 18G i need atleast 20G on the Host to Host. how can i optmize or configure these NICs to achieve the required bandwidth.
Kind Regards
cecilio. K
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DELL-Erman O
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January 25th, 2023 05:00
Hi, it is possible that the 18Gbps is the bottleneck imposed by some other component, like the switch, cables, or even the VMkernel configuration. It is hard to say what causes that directly for me.
Network configuration for PowerEdge blade servers and vSphere Distributed Switch configuration for LAN traffic topics may help. https://dell.to/3j64Cau Anyone in the community welcomes to share their experience.
Regards,
kisitu
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January 25th, 2023 07:00
Hello Erman,
The irony is this is a blade system meaning it plugs directly into the back plane and you would expect to get the maximum speeds especially when the node is in the same chassis meaning the devices involved would be the NIC, Back plane and the Smart switch Fabric.
When i checked on the speeds of the interface on the smart switch fabric with in the chassis, it showed 25G.however when u ran tests from the host to host 18G
and when u migrate the vms into the same ESXI host, you get more than 30G on the vms so the puzzle is on vms on different hosts.
on my vmware environment i use vmxNet3 adapters
Regards
Cecilio K
DELL-Erman O
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January 26th, 2023 00:00
Hi, considering what you've stated, I tried to think of the possibilities. I'm just brainstorming. Maybe vmxNet3 adapter is not set for 25Gb or you can try to increase the amount of bandwidth reservation resources allocated in vswitch configuration. If the vmxNet3 adapter is not optimized for high bandwidth, it can be checked via a new adapter. Such as the vmxNet4 adapter, which is optimized for high-speed networking. The reason I'm considering this possibility with vmxNet3 is vmxNet3 adapters when communicating between different hosts. Sorry, I'm not a pro at this, just thinking.
Regards,