RunNSX

Came across this in my current engagement.  Was happening on one of the servers in the Payload Cluster, which was a fresh install of 6.0.0, 2494585

After upgrading to or installing ESXi 6.0.x and ESXi 6.0 Update 1, you may experience these symptoms:

• ESXi 6.0 host network connectivity is lost randomly
• ESXi enters into a non-responding state and becomes unmanageable until reboot
• Network connectivity does not return until the ESXi 6.0 host is rebooted
• After rebooting, the issue is temporarily resolved for a period of time, but occurs again after a random interval unless the workaround (script) is implemented

In the /var/log/vmkernel.log file, there is evidence of transmit timeouts.  This is often logged by the NETDEV WATCHDOG service in ESXi. You may see entries similar to:

YYYY-MM-DDT21:35:34.007Z cpu0:33245)WARNING: LinNet: netdev_watchdog:3678: NETDEV WATCHDOG: vmnic0: transmit timed out
YYYY-MM-DDT21:35:34.007Z cpu0:33245)WARNING: at vmkdrivers/src_92/vmklinux_92/vmware/linux_net.c:3707/netdev_watchdog() (inside vmklinux)

This issue can impact multiple network adapter types across multiple hardware vendors The exact logging that occurs during a transmit timeout may vary from card to card.

Note: This issue does not affect ESXi 5.5 and earlier releases, only ESXi 6.0 is affected.

This issue is resolved in ESXi 6.0 Update 1a, available at VMware Downloads. For more information, see the VMware ESXi 6.0 Update 1a Release Notes.

ESXi 6.0 network connectivity is lost with NETDEV WATCHDOG timeouts in the vmkernel.log (2124669)