yum -y install nfs

[root@iZ25o0ipjpmZ /]# /etc/init.d/nfs start
Starting NFS services:                                     [  OK  ]
Starting NFS quotas: Cannot register service: RPC: Unable to receive; errno = Connection refused
rpc.rquotad: unable to register (RQUOTAPROG, RQUOTAVERS, udp).
                                                           [FAILED]
Starting NFS mountd: rpc.mountd: svc_tli_create: could not open connection for udp6
rpc.mountd: svc_tli_create: could not open connection for tcp6
rpc.mountd: svc_tli_create: could not open connection for udp6
rpc.mountd: svc_tli_create: could not open connection for tcp6
rpc.mountd: svc_tli_create: could not open connection for udp6
rpc.mountd: svc_tli_create: could not open connection for tcp6
                                                           [FAILED]
Starting NFS daemon: rpc.nfsd: writing fd to kernel failed: errno 111 (Connection refused)
rpc.nfsd: address family inet6 not supported by protocol TCP
rpc.nfsd: unable to set any sockets for nfsd
                                                           [FAILED]

解决：

[root@iZ25o0ipjpmZ /]# /etc/init.d/rpcbind start
Starting rpcbind:                                          [  OK  ]
[root@iZ25o0ipjpmZ /]# /etc/init.d/rpcidmapd start
Starting RPC idmapd:                                       [  OK  ]
[root@iZ25o0ipjpmZ /]# /etc/init.d/nfs start
Starting NFS services:                                     [  OK  ]
Starting NFS quotas:                                       [  OK  ]
Starting NFS mountd: rpc.mountd: svc_tli_create: could not open connection for udp6
rpc.mountd: svc_tli_create: could not open connection for tcp6
rpc.mountd: svc_tli_create: could not open connection for udp6
rpc.mountd: svc_tli_create: could not open connection for tcp6
rpc.mountd: svc_tli_create: could not open connection for udp6
rpc.mountd: svc_tli_create: could not open connection for tcp6
                                                           [  OK  ]
Starting NFS daemon: rpc.nfsd: address family inet6 not supported by protocol TCP
                                                           [  OK  ]
[root@iZ25o0ipjpmZ /]#                                     [  OK  ]

RH系操作系统在6.0版本之后没有portmap服务控制rpc的启动，由于NFS和nfslock的启动需要向rpc进行注册，rpc不启动的话就会报错。
解决方法：启动rpcbind&rpcidmap rpcbind是6.0版本后默认的RPC服务，所以要先于nfs启动。如果不启动rpcidmap则会造成用户权限的映射错误，用户的权限看起来是一串数字。