I have a small host running Fedora 18 (3.6.11), with a nfs set to server a /mnt/dir.
The problem on the client running Fedora (3.11.6) after just a minute or so the mount disappears. SELinux is disabled on both host and client, and I am able to see the nfs mount on client and both read and write to it. But after a few minutes it dissapears.
my-serv:/mnt/server /mnt/share/ nfs4 rw,noatime,rsize=32768,wsize=32768,intr,hard 0 0
After mount -a,
$ ls -l /mnt/share/ -rw-r--r-- 1 root root 0 Jun 22 05:50 test ......
a few moments later,
$ ls -l /mnt/share/ total 0