Hello.
A few weeks ago, I ran into the "netdev_watchdog" problem and downgraded my hosts back to ESXi 5.5.
Re: ESXi 6.0 causing Dell C6100 XS23-TY3 to hang randomly
On friday i gave ESXi 6 a second try and upgraded my hosts from 5.5 to 6.0U1.
Yesterday I had a similar issue which also seems not to be the "netdev_watchdog" problem (which should be fixed with 6.0U1).
But in my case, the host lost the network connections, which is really bad since we use iSCSI storage.
The host was disconnected from vCenter and also not acessable via ESXCLI, DCUI or SSH.
I had to power off the hardware to trigger VMware HA to restart the hosted VMs.