Why Ubuntu's LTS releases are inferior to Red Hat Enterprise Linux
It's time to update my view of Ubuntu with my most recent set of feelings. Well, with why I feel my most recent set of feelings, which is that Ubuntu LTS is significantly inferior to Red Hat Enterprise Linux.
Ubuntu's LTS releases (Ubuntu 6.06 and Ubuntu 8.04) promise five years of support (hence the 'Long Term Support' label). This support is why we're able to consider them, since we need more than 18 months of support that you get with regular Ubuntu releases; we're simply not in a position to update our servers that frequently.
(There are two reasons. First, moving operating systems in a production environment requires a fairly large amount of careful testing (and a certain amount of dealing with changes). Second, we run login servers and our users do not want to have to do migration work that frequently either; they have better things to do with their time, like complete their PhDs or do research.)
The problem is that in practice Ubuntu's 'long term support' is actually only 'long term security fixes'. I have almost never seen Ubuntu fix a problem that was not a security problem, even when the problems are reported in Ubuntu's bug report system (and in one case, even when the problem let an ordinary user crash the kernel). The inevitable result is that we have an ever-growing catalog of bugs in 6.06 that will never be fixed.
(I think that Ubuntu does fix bugs under some limited circumstances; what they really don't seem to do is fix bugs when the fix would require backporting things into the old 6.06 version of packages.)
By contrast, something like Red Hat Enterprise Linux does provide real long term support, where even non-security bugs will be fixed (at least for a while). This is not just theoretical, in that I have seen actual RHEL packages released to backport fixes for mere bugs.
(I am also relatively certain that Red Hat would consider 'user can crash the kernel' to be a security bug.)
Ubuntu, LTS releases included, still has an unmatched selection of packages (and is what users have heard of, which matters more than you might think). But there is less and less enthusiasm here for running it on 'backend' machines, machines that users don't log in to or run programs on, and I can't say that we're very enthused about it even on the login servers.