One of five servers disconnecting once every 24 hours

[JMiller24]

Hi all,

We are running two hosts in a vCenter cluster with 5 win 2012 VMs. All running the E1000 NICs in VMware. It seems like once every 24 hours one of the VMs will lose connectivity (NIC will be X'd out) and it won't be restored until we reboot the server.  It can happen to any of the 5 VMs.  The event logs aren't showing anything.  Any advice?

(I apologize if some of this doesn't make sense, I am posting this for the boss, who is currently driving,  and  I am not very VM savvy)

Edit: I forgot to mention we are on 5.5

[tomtom901]

Try switching out those E1000's for VMXNET3. To use VMXNET3, ensure that the VMware Tools are installed on the guest OS (Win 2012) as this package includes the drivers for the VMXNET3 network adapter. The VMXNET3 is the next-generation paravirtualized network adapter, offering lower overhead (CPU) on the host and more throughput (10 gigabit).

[OscarDavey]

Try this :

1. Place the ESXi/ESX host into maintenance mode.
2. Remove all VMNICs from the virtual switches except vmnic0, which is used for management.
3. Shut down the ESXi/ESX host.
4. Remove/disable all NICs except vmnic0.
5. Boot the server. At boot time, all removed/disabled VMNICs are removed from the esx.conf file.
6. Shut down the ESXi/ESX host.
7. Add/enable all required NICs.
8. Boot the ESXi/ESX host. All VMNICs are assigned per segment, bus, slot, and function ID, and are ordered correctly.
9. Assign VMNICs back to virtual switches as before.
10. Exit maintenance mode on the ESXi/ESX host.

Hope this will help you out .

Best regards

Yours, Oscar

[JMiller24]

Thank you so much guys. The boss should be getting in soon, and we can try some of that. I'll let you guys know the results.   Very much appreciate the advice, especially today when you guys should all be taking it easy!

[tomtom901]

I would suggest starting with my post, as it is the least disruptive to the VM's and the ESXi host. Also, if you perhaps could share a screenshot of your configuration -> networking via the vSphere client, we might get a better understanding of your enviroment.

A few things to check / clarify:

1) Does the ESXi host lose connectivity as well when the VM's lose connectivity?

2) Does only one VM lose connectivity at a time? So, if one loses, the other 4 still work?

3) I'm not really sure what you mean by X'ed out. Do you mean that in Windows, the NIC is in a disconnected state? If so, check on the settings of the NIC if the NIC is still connected:

4) When you say "reboot the server", do you mean the VM or the entire ESXi host?

5) Unlikely, but do the physical switchport(s) the ESXi host is attached to, report any errors?

Most of the festivities have already ended here, so back to work now :smileyhappy:.