That’s a very vague subject line, I know, but I couldn’t think of anything concise. Just wanted to put some keywords so that if anyone else comes across the same problem and types something similar into Google hopefully they stumble upon this post.
At work we got some HP DL360 Gen9s to use as ESXi hosts. To these servers we added additional network cards –
- HP FlexFabric 10Gb 2-port 534FLR-SFP+ Adapter; and
- HP Ethernet 10Gb 2-port 530SFP+ Adapter.
Each of these adapters have two NICs each. Here’s a picture of the adapters in the server and the vmnic numbers ESXi assigns to them.
- vmnic5 & vmnic4 are the HP FlexFabric 10Gb 2-port 534FLR-SFP+ Adapter;
- vmnic6 & vmnic7 are the HP Ethernet 10Gb 2-port 530SFP+ Adapter; and
- vmnic0 – vmnic3 are HP Ethernet 1Gb 4-port 331i Adapter (which come in-built into the server);
- iLO is the iLO port (which I’ll ignore for now).
We didn’t want to use vmnic0 – vmnic3 as they are only 1Gb. So the idea was the use vmnic4 – vmnic7. Two NICs would be for Management+vMotion (connecting to two different switches); two NICs would be for iSCSI (again connecting to different switches).
We came across two issues. First was that the FlexFabric NICs didn’t seem to support iSCSI. ESXi showed two iSCSI adapters but the NICs mapped to them were the regular Ethernet 10Gb ones, not the FlexFabric 10Gb ones. Second issue was that we wanted to use vmnic4 and vmnic6 for Management+vMotion and vmnic5 and vmnic7 for iSCSI – basically a NIC from each adapter such that even if an adapter were to fail there’s a NIC from another adapter for resiliency. This didn’t work for some reason. The Ethernet 10Gb NICs weren’t “connecting” to the network switch for some reason. They would connect in the sense that the link status appears as connected and the LEDs on the switch and NICs blink, but something was missing. There was no real connectivity.
Here’s what we did to fix these.
But first, for both these fixes you have to reboot the server and go into the System Utilities menu.
Change 1: Enable iSCSI on the FlexFabric adapter (vmnic4 and vmnic5)
Once in the System Utilities menu select “System Configuration”.
With this change the FlexFabric NICs will appear as iSCSI adapters. Now for the second change.
Change 2: Enable DCB for the Ethernet adapters
From the System Configuration menu now select the first Ethernet NIC (port 1).
I have no idea what DCB does. From what I can glean via Google it seems to be a set of extensions to Ethernet that provide “hardware-based bandwidth allocation to a specific type of traffic and enhances Ethernet transport reliability with the use of priority-based flow control” (via TechNet) (also check out this Cisco whitepaper for more info). I didn’t read much into it because I couldn’t find anything that mentioned why DCB mattered in this case – as in why were the NICs not working when DCB was disabled? The NICs are connected to an HP 5920AF switch but I couldn’t find anything that suggested the switch requires DCB enabled for the ports to work. This switch supports DCB but that doesn’t imply it requires DCB.
Anyhow, the FlexFabric adapters have DCB enabled by default which is probably why they worked. That’s how I got the idea to enable DCB on the Ethernet adapters to see if it makes a difference – and it did! The only thing I can think of is that DCB also seems to include a DCBX (Data Centre Bridging Exchange) protocol which is about discovering peers, discovering mismatched configuration etc – so maybe the fact that DCB was disabled on these adapters made the switch not “see” these NICs and soft-disable them somehow. That’s my guess at least.