So I rent a dedicated server from a datacenter that's running CentOS 5.8. I want to upgrade it to CentOS 6.3. My problem is I have a bunch of web sites and a bunch of servers running on the box already; so doing a fresh upgrade is nearly impossible. (Nearly 1TB worth of data I'd have to backup)

So is it possible to update a distro, without doing a fresh install, remotely?

1. What is the benefit/goal of upgrading to 6.3? (so that you can weigh it against the time/expense/effort of the upgrade)
2. Why isn't your data backed up already??
3. Have you seen this? (1st Google hit for "upgrade CentOS"): http://wiki.centos.org/HowTos/MigrationGuide
4. There may be additional migration documents available at RedHat.com (CentOS is based on Red Hat) although as far as I know Red Hat does not officially support upgrades across major releases.

1. Because I need a newer version of GLIBC than what's installed on CentOS 5.8. I need version 2.11 or higher, yet the highest I can seem to get on 5.8 is 2.5. Therefore, I need to upgrade to run the software I intend to run.
2.It is backed up, but uploading 1TB worth of data remotely on a 1mbps connection would literally take almost 3 months at full speed. That's the fastest my home connection can upload data.
3.I did try viewing that page this morning, but it was down for some reason. I'll check it out now; thanks.
4.Well I guess it's pointless to go any further then if I can't upgrade across major releases. Bummer.