@nikade Yeah, that is a far from optimal setup. It will force the data to flow through the management interface before being routed to the storage NICs.
Running iostat and xtop should show the load. A better configuration IMO would be putting the storage NICs on the switch and using a separate network or VLAN for the storage I/O traffic.
Storage I/O optimization takes some time and effort. The type, number, and RAID configuration of your storage device as well as speed of your host CPUs, eize and type of memory, and configuration of your VMs (if NUMA aware, for example) all will play a role.