maybe someone has encountered a similar behavior as we ...
We had the issue that during a bios update on the server , the Nexus 5k disconnected the FEX were the server was connected.
The issue happened on different 5k versions with different Server hardware - only common piece is a broadcom card.
According to Cisco TAC the issue is that the server NIC is sending massive amount of Pause frames during the bios update which is causing the 5k to disconnect the FEX to save the Nexus CPU from overloading .. THis should also only apply to Nexus 5k as Nexus 9k is behaving different in handling the Pause frames
This sounds just strange to me - why should the NIC send pause frames ... we did the BIOS update on about 400 servers and it happened only on 2 machins.
The update killed both FEX where the server was connected - so it killed all servers which were connected to both FEXs.
Just wanted to know if someone has seen something similar