vagrant 设置nfs 后reload报错问题?报错

osx 10.9
virtualbox 4.3
vagrant 1.71

vagrantfile主要配置如下：

config.vm.provider :virtualbox do |vb|
    #vb.gui = true
    vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
    vb.customize ["modifyvm", :id, "--natdnsproxy1", "on"]
  end

  config.vm.network :private_network, ip: "192.168.10.10"
  config.vm.synced_folder "/Volumes/Data/vagrant-webroot", "/home/www/webroot", type: "nfs"

osx以及centos镜像中均安装nfs