So here’s the deal: Scientific Linux is a damn good clone of Red Hat Enterprise Linux, but there are some differences between it and the upstream product. I found out about one today when I noticed doing a “yum update” didn’t bump my 6.0 system up to SL 6.1, even though that updated version is now available.
This is by design. As one of the SL maintainers, Troy Dawson explains:
The default setting for Scientific Linux is for you to “sit on a release”. This means that you do not automatically update to the next release, unless you want to. So if you install SL 5.4, you will stay at SL 5.4, getting security updates, until you manually update to whichever release you want.
If you want the same functionality as RHEL (your machine is automatically updated to the latest release) you need to install yum-conf-sl6x.
In my case I just did a yum install yum-conf-sl6x and then ran yum clean all, yum update. When it was all over my /etc/redhat-release file said:
Scientific Linux release 6.1 (Carbon)