I have setup static route but it didn't make any different.

However, the problem was solved after I reconfigure Open-E DSS MPIO to Round Robin and set iops to 1 using this command as instructed by the your guide [Open-E_DSS_V6_MPIO_with_ESX4i_4.1.pdf]:

esxcli nmp roundrobin setconfig --type "iops" --iops 1 --device <device UID>