Depends what the failure is. If it is due to a corrupt rpm database, then a cure that often works is to run something like the following:
[root@bright60 ~]# rm /var/lib/rpm/__db.*
rm: remove regular file '/var/lib/rpm/__db.001'? y
rm: remove regular file '/var/lib/rpm/__db.002'? y
rm: remove regular file '/var/lib/rpm/__db.003'? y
rm: remove regular file '/var/lib/rpm/__db.004'? y
[root@bright60 ~]# rpm --rebuilddb
[root@bright60 ~]# yum clean all
Then, run yum update again. If that doesn't solve the issue, filesystem corruption may be a culprit.
Possibilities to consider that may have caused the issue:
- Killing yum commands brutally
- filesystem corruption
- inconsistency in repository database due to it being in the middle of a major update
- descent into RPM dependency hell due to installation of software from outside the repository
- other.
If it is not a corrupt yum database, then consider these possibilities:
- one possibility is that you are behind a proxy. In that case, see /faq/index.php?action=artikel&cat=9&id=142
- It is also possible that the yum broker (a load balancer for distributing the load of yum package downloads to various yum mirrors) is not working correctly. In that case a direct mirror such as http://mirror.utexas.edu/epel/ can be used instead.