Maybe somebody could had before the same problem that I've got right now.
I've got FAS2554 Ontap 9.1 connected with FO (10Gb) to Extreme x440. the clients are Redhat 6.8 Server.
I defined tagged interfaces at both sides (Netapp/Redhat) to allow access thru NFS from Redhat to NETAPP.
The maximum speed that I've got using VLAN Tagged is 1MBps
To discard wrong switch configuration, I connected a wire directly from NETAPP e0a to Redhat Server (VLAN enabled), the results was the same.
If I set no VLAN at both sides and repeat the test, the speed grow up until 100MBps.
This is the configuration for Redhat tagged interface
I would be pleased if somebody could assistme with the problem.