yum makecache 报错

file:///media/CentOS/repodata/repomd.xml: [Errno 14] Could not open/read file:///media/CentOS/repodata/repomd.xml

Trying other mirror.

file:///media/cdrom/repodata/repomd.xml: [Errno 14] Could not open/read file:///media/cdrom/repodata/repomd.xml

Trying other mirror.

Error: Cannot retrieve repository metadata (repomd.xml) for repository: c6-media. Please verify its path and try again

这是什么意思啊，应该怎么解决