今天在电脑上装了个Centos5.3的系统，接着装了个yum源，

yum文件： [feng]

          name=yum server

          baseurl=file:///mnt/CentOS

          gpgcheck=0

但是一直提示报错:

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
file:///mnt/CentOS/repodata/repomd.xml: [Errno 5] OSError: [Errno 2] 没有那个文件或目录: '/mnt/CentOS/repodata/repomd.xml'
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: CentOS-Base. Please verify its path and try again

后来发现，其实是yum找不到光盘的rpm索引文件repomd.xml，最后，把/mnt/CentOs 更改为/mnt即可。