invalid argument is a mount reply
probably you receive it because you did not install the support for rdma
if you did not install cifs-utils you receive the same result from mount -t cifs
try to
yum groupinstall "Infiniband Support"
NFSoRDMA incorrect mount option
Re: NFSoRDMA incorrect mount option
Ok I figured it out! The OFED driver has this disabled by default. I had to reinstall it with ./mlnxofedinstall --with-nfsrdma