During a rolling reboot a couple of NFS clients reported issue as “nfs mount points hung/df –k not responding” and rebooted the client nodes to fix the issue.

Clients were running RHEL 7.6 and NFS v3

Mount paramters

rw,relatime,vers=3,rsize=131072,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=x.x.x.x,mountvers=3,mountport=300,mountproto=udp,local_lock=none,addr=x.x.x.x

The network pool is set to dynamic allocation

As I understand it the nfs clients should not see disruption during a rolling reboot?

The users are keen to understand why this occurred and to prevent a recurrance during a planned OneFS upgrade