Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
http://ftp.sjtu.edu.cn/centos/5.4/addons/x86_64/repodata/primary.sqlite.bz2: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
Error: failure: repodata/primary.sqlite.bz2 from addons: [Errno 256] No more mirrors to try.
yum clean all
yum makecache
解決問題