Thanks for the pointers - bonding was an experiment. Switch is an edgerouter 12 which indeed supports LACP, though I was unable to configure this properly (illegal loop-backs were occurring when both eth0 and eth1 were plugged in.) I rebooted the machine and now unraid is functioning properly which is strange but welcome. Only other anomaly was that I did stop an unscheduled parity check after accidental hard shutdown. If nothing here is out of the ordinary I will just close the ticket then and hope that I don't encounter this again.