I keep getting lockups and hanging delays with my NFS setup, so I continue to experiment.
Server /etc/exports:
/var/www *(rw,sync,fsid=0,no_acl,insecure,insecure_locks,no_subtree_check,no_root_squash)
Client /etc/fstab:
192.168.8.91:/dev/ /mnt/imports/dev-91-gl nfs4 rsize=1024,wsize=1024,hard,rw,timeo=4,intr,proto=udp 0 0
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