Enumeration of VMNICs

[StephenMoll]

How is the enumeration of physical NICs to VMNICs done in ESXi?

We are noticing a difference in the order in which this occurs between different batches of hosts? What are the potential reasons for this?

Can we influence the enumeration order in any way to ensure consistency?

The compute platforms are Dell M1000e blades. On one batch of blades (the newest ones) the enumeration of the fabric NICs to VMNIC numbers is the same for v5.1 and 6.5 of ESXi. With the oldest ones, the enumeration order is different. Some clues as to why this happens would be much appreciated.

[Tibmeister]

If memory serves, they are enumerated in order of appearance on the PCI bus, but here's a KB that details how this is done in ESXi 5.5 and above.

VMware Knowledge Base

[StephenMoll]

Ah! That looks very interesting. I'll take a closer look at that on Monday.

Many thanks.

[NathanosBlightc]

ESXi has a device manager that will retrieve the list of available devices on the motherboard to assigns their device name. So in most of times it will consider locally onboard devices for numbering, then other installed devices on motherboard slots (like PCI-E NICs). Just remember following points:

1. Device replacement don't change existing port numbers.

2. If you remove a device, it's Alias name will be available for using on next names

3. If there is a different numbering in rear cases like your issue or after an upgrade, you can fix it by Host Profile feature.

[StephenMoll]

Are there any known differences between v5.5 and v6.5 in the way the enumeration works?

In case my original explanation isn't clear?

For the original blades, ESXi 5.5 and 6.5 produce a different vmnic to physcial port mapping.

For the revised (newer batch) of blades, ESXi 5.5 and 6.5 produce the same mapping.

The problem is that the blades are supposed to be interchangeable, but with the various ports aligned to different networks for different purposes, the behaviour described above results in some problems for us.

[NathanosBlightc]

Are there any known differences between v5.5 and v6.5 in the way the enumeration works?

I don't think there is any architectural different for adapter enumeration (I Checked the vSphere 6.5 Networking Guide Docs)

But you can change the order of the adapter manually. Check this link