VMXNET3 DirectPath I/O Enabled

Hello,

Contara from Zerto Support.

The VRA is deployed with a VMXNET3 adapter, which is a 10 Gbps vNIC. A VRA cannot utilize multiple vNICs to improve throughput. This means that a single VRA is bound to 10 Gbps, or 1,250 MBps as a theoretical maximum.

Thank you.

Hi Contara,

Being that the VRA is limited to one vNIC, it seems DirectPath I/O is turned on by design to provide better performance? Looking for clarification. Thanks!

Hi,

This is Kalsang from Zerto support.

Yes, DirectPath I/O is turned on by design to provide better performance.

Best regards,

What if we’re utilizing Nutanix clusters with ESXi hypervisor? From what Nutanix keeps telling me. Due to the storage locality, the Direct Path I/O option is recommended to be disabled on all VMware virtual machines.

Would we still keep it enabled for just the Zerto VRA VM’s?

I understand the use case for Direct Path if running a tiered architecture like a Flex-Pod or something. Considering vxRail and Nutanix hyper-converged designs, is this still the case?

Hello Joseph,

I am Joseph with Zerto. I am investigating your inquiry and will provide a status soon.

Thank you,

Joe

Hello Joe, thank you! Our Nutanix reps had let us know that Nutanix technology doesn’t utilize the DirectPath I/O option, though in some situations, depending on the application it could be a different scenario.

For the most part, DirectPath I/O doesnt support vmotion, Fault Tolerance, HA or snapshots. Though, I also know the Zerto virtual appliances do not really use any of those functions.

Thank you in advance for your time and efforts.

-Joseph

Hello Joseph,

I have a request out to our product team. Once I receive an update I will post a response.

Thank you,

Joe

Hello,

I continue to follow up with our product team regarding this inquiry. I will provide an update when available.

Thank you,

Joe

Hello,

I  received feedback from our product team. Regarding the VRA and Direct Path I/O, there is no impact on the VRA itself and it can be turned off for the VRA. I hope this was helpful. Thank you.

Joe