On VMware ESX 5.5 running on an E9000 equipped with the MZ910+CX911, the vm-support command causes storage link disconnection.
Monitor the status of the MX510 switching plane and run the vm-support command. The CLI shows that when the lldpnetmap command is invoked, the status of all storage links in the chassis is link-down.
When the /sbin/lldpnetmap command is run, LLDP is used to obtain the networking information of the NIC and switch board. The MZ910 works in FCoE mode. Therefore, the system delivers LLDP packets using the Vmnic network port name. The MZ910 periodically sends LLDP packets in MAC address format to perform DCBX link negotiation. If two different LLDPDUs are received through the same LLDP link, FCoE_GW detects different LLDP packets on the point-to-point link and identifies them as different neighbors. Therefore, the FCoE_GW clears the DCBX connection and establishes a link again. As a result, the HBA exits the registration and re-registers, causing disconnection from the storage device.
Suppress the lldpnetmap command by changing the file name.