How to fix Lost connectivity to the device backing the boot filesystem ?
Error: Lost connectivity to the device naa.60xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx backing the boot filesystem /vmfs/devices/disks/naa.60xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx. As a result, host configuration changes will not be saved to persistent storage.
If we lose connectivity to the NIC that runs the boot LUN (switch reboot, cable disconnect, etc.), we will see the above error. This error is being displayed because connectivity is lost and the iSCSI boot does not support Multi pathing, which means that if connectivity is lost between the Storage Processor (SP) on the VNXe and the NIC on the host, the host can no longer access its boot lun and cannot write logs etc.
There is no impact as whole ESXi OS is loaded into memory so there is no outage for the VMs. Once the connectivity is restored the host can access the storage again. The error was for the fact that the error does not clear automatically.
The simplest solution is to put the host into maintenance mode, reboot it and the problem is solved Or restart the Management Agents on the ESXi host.