我刚刚安装了 CentOS 6。我尝试运行 yum update 并且无法让它工作，所以我尝试了 yum clean all，现在我的情况似乎比以前更糟。根据我在下面粘贴的内容，有人可以帮我修复我的 yum 存储库吗？谢谢。
[root@zedo-pc 1234]# yum update
Loaded plugins: fastestmirror, refresh-packagekit
Loading mirror speeds from cached hostfile
* base: mirror.7x24web.net
* extras: mirror.linux.duke.edu
* updates: mirror.lug.udel.edu
Error: no such table: packages
[root@zedo-pc 1234]# yum clean all
Loaded plugins: fastestmirror, refresh-packagekit
Cleaning up Everything
Cleaning up list of fastest mirrors
[root@zedo-pc 1234]# yum update
Loaded plugins: fastestmirror, refresh-packagekit
Determining fastest mirrors
* base: mirror.lug.udel.edu
* extras: mirror.symnds.com
* updates: mirror.rackspace.com
Error: Cannot retrieve …