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Hi, Is it possible to enable SR-IOV on a VM hosted on an ESXi participating to a cluster ?

Hi, Is it possible to enable SR-IOV on a VM hosted on an ESXi participating to a vsphere cluster environment ?
Besides, how can we disable this feature on a VM if needed.
thank you so much
Avatar of Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
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SR-IOV is supported from VMware vSphere 5.1 (ESXi 5.1).

SR-IOV capable network cards can enable this function on the physical device in the ESXi host, when the physical network interface in the host is presented to the virtual machine in passthrough mode (e.g. VMDirectPath I/O).

So do you have any VMs, that use VM Direct Path I/O, e.g. presenting the network interface direct to the VM.

if not then you have nothing to be concerned about, it is disabled.

if you do have VMs using an network interface in VM Passthrough (VM Direct Path I/O), you have to enabled SR-IOV, it's not enabled by default.

So in Summary

Do you have any VMs with a physical interface presented to them using VMDirect Path I/O ?

Is it enabled for SR-IOV ?
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ASKER

Thank you for clarifying that for me.

In fact, we are going to enable the SR-IOV for a specific VM and we would like to meet all the requirements...

As per the KB 2038739, SR-IOV cannot be configured for a VM participating in cluster environment.

So, if we would like to enable SR-IOV it should be done fo a VM hosted on an ESXi which is not a part of a cluster, right?

Thanks once more.
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Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
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ASKER

Thanks Andrew for your clear and helpful answers.

One last point, I would like to confirm with you the two following steps for disabling SR-IOV on a host if needed :

1. set the max_vfs parameter to 0
2. Then restart the host.
Is the physical interface presented to the VM ? if the nic is not presented to a VM, then it does not matter, the nic is not used.

Check in the Web Client if ENABLED, and DISABLE it.

You can also check whether a nic supports SR-IOV , if it does not then the question is also not applicable.
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ASKER

I didn't enable it yet .... but I'm asking in case if I need to disable SR-IOV once enabled.

Many articles explain in details how to enable SR-IOV but I cannot find a KB or an article with all the steps to be followed in order to disable SR-IOV if it is already enabled.
Just select disabled.

also, not all nics are supported.