Am 24.07.2011 14:04, schrieb Always Learning:
The challenge is how to do an easily transition from one major version to its successor version with the least physical, emotional, intellectual and time-consuming effort.
Paul,
as much as I understand your point of view, I must disagree taking upstream's and CentOS's position. Your description reflects a home user or an administrator with just less than a handful of systems.
CentOS and RHEL aims for the enterprise use. Of course that does not imply people can not rely on this stable platform in very small environments, but that's not the focus of the OS design. And speaking about the enterprise scenario, no serious administrator will risk the proper function of his install base by going risky paths. Typically the OS is just the base for the middleware and application level. Switching to a new major level of OS with lots of important changes means, the administrator will have to test and adjust his setup of OS and application use in multiple aspects. This even applies to applications the base OS ships with.
In enterprise environments, where the CentOS systems are more than a simple shell box or a trivial webserver, it is more time consuming to find all the possible places to adjust the obsolete configurations being transferred by an upgrade and to find the tripping points than to run a clean and fresh installation with a defined state. In less trivial setups the applications even get wrecked because of library changes and such.
I am a sysadmin for an enterprise running both RHEL and AIX...both of them being enterprise level OSes.
IBM has managed to support in place upgrading of their OSes from one major version to another for several versions, now...in fact, each release is, according to IBM, a separate release, with technical levels or maintenance levels and service packs being in-level patches.
So, going from 5.3 TL6 SP6 to 5.3 TL12 is as considered patching and is as simple as running "smitty update_all" from within an appropriately configured repository directory (or directories), much like running "yum update".
On the other hand, going from 5.1 anything to 5.2 anything, 5.2 to 5.3, 5.3 to 6.1 is considered a major release...and upgrading those, in place, is fully supported by IBM, and is as simple as either booting from an appropriate boot disk, or using the appropriately configured NIM boot and install/up process.
If IBM can make this happen for their OS, and Red Hat certainly supports such a process in the Fedora line of releases (including the ability to list additional repositories for remote installation as part of the process), they could certainly make it a supportable option for the RHEL line.