Drupal File system 错误:The directory sites/default/files does not exist解答

Linux系统，Drupal初学者必定会遇到的一个小问题：

在本地安装或者站点完成上传到网络之后遇到这个提示：

File system
The directory sites/default/files does not exist. An automated attempt to create this directory failed, possibly due to a permissions problem. To proceed with the installation, either create the directory and modify its permissions manually or ensure that the installer has the permissions to create it automatically. For more

原因是在linux系统中存在的权限问题

解决的办法：在  sites/defaule 目录下 新建一个目录  files 

注意files 文件夹的权限，必须是777，否则仍然报错