I have 6 servers which were configured to be Windows systems (including our domain controllers) on top of ESXi. They are on Cisco UCS B200 M3 and UCS B400 blades inside a UCS 5108. They have no internal storage thus configured to boot from network storage. The network storage is the NetApp 3250 with storage shelves. At one point all of the blades stopped booting.
We have had Cisco help us examine the configuration of the blades and the fabric through the UCS manager. They off course point the finger toward the NetApp. The LUNs on the 3250 can be readily sees as the configured boot LUNs for the respective blades, but still nothing happens. These blades have been booting fine for over two years then suddenly about 10 days ago everything stopped.
I have no idea where to look to find the problem or how to restore connectivity. Any help would be appreciated.