Thanks to everyone for all the helpful suggestions.
Through experimentation we discovered that we cannot mix LACP and VLAN tagging. We don't know if it's the switch or ONTAP and we haven't seen any documentation or bug reports.
The switch is a stack of two Nortel units. Didn't note the model, but each unit has 48 ports each 1Gbit.
So we reconfigured the switch for "multi" trunking and VLAN tagging and all is working as expected:
First head:
vif create multi vifb -b ip e0b e6b vif create multi vifc -b ip e0c e6c vif create single vif0 vifb vifc # favor switch unit 1 vif favor vifb vlan create vif0 201 202 ifconfig vif0-201 192.168.5.6 netmask 255.255.255.0 partner vif0-201 ifconfig vif0-202 192.168.15.6 netmask 255.255.255.0 partner vif0-202
Second head:
vif create multi vifb -b ip e0b e6b vif create multi vifc -b ip e0c e6c vif create single vif0 vifb vifc # favor switch unit 2 vif favor vifc vlan create vif0 201 202 ifconfig vif0-201 192.168.5.8 netmask 255.255.255.0 partner vif0-201 ifconfig vif0-202 192.168.15.8 netmask 255.255.255.0 partner vif0-202
Steve Losen scl@virginia.edu phone: 434-924-0640
University of Virginia ITC Unix Support