Cannot backup dump file to nfs filesystem. After tested more options, I found that we just change the version from 3 to 2.
mount -o cio,rw,bg,hard,nointr,rsize=32768,wsize=32768,proto=tcp,noac,vers=2,timeo=600 nfsserver:/share /share
For new environment. Just mount with a little option. This working fine.
mount -o rsize=32768,wsize=32768 172.18.1.231:/backup /backup