I have a 2012 R2 server configured to export a folder over NFS to Linux clients using defaults to mount. After the server reboots, the clients are able to read attributes once again after a minute or two but all the initial read/write operations appear to hang for what seems to be 10 minutes or so before finally successfully going through. Thereafter all I/O happens as I would expect it to. This doesn't appear to relate to what point in the reboot that the server itself is in. If I wait ten minutes after it's finished booting the first I/O still hangs.
I was wondering what the cause of the hang could be and if it's possible to lessen the amount of time it takes for the NFS servers to be responsive.