Well, I upgraded my primary internet server (I have a top level domain that I own, plus misc. services) yesterday from Red Hat Linux 8.0 to Red Hat Enterprise Linux version 3 Advanced Server. The upgrade went fine as far as the software is concerned. The hardware is a different issue. My primary filesystem is on a software RAID5 array. In a RAID5 array you can loose any 1 disk and it still keeps working (assuming you don’t have any hotspares, which I don’t). I had two disks give me sector errors during the upgrade. I had to take the machine into rescue mode, reassemble the array with 1 of the failed disks marked as good forcefully, then replay the ext3 journal, then fsck the filesystem, then hot add the other failed disk and let it get rebuilt. Only after all that was done could I redo the upgrade to finish it and make sure no files were corrupted. After completing that, it only took some minor tweaks to get things working under RHEL3 the way they did under RHL 8.0. Whew! Only roughly 1 day of downtime total ;-)