On Thu, 3 Jul 2008, Axel Thimm wrote:
I start to think whether these kernels are indeed being all used to the extend of justifying full kmdl support. Maybe it would make sense to keep the full last series (2.6.18-92* above) and the highest one from the series before (2.6.18-53.1.21.el5 and 2.6.18-8.1.15.el5).
While Red Hat has promised initially a stable ABI within a version (including all updates), this was not always the case - or maybe it isn't clear to me what this promise means. However, the breakages are much more likely to occur when major updates (like RHEL 5.2) come while the minor kernel updates (like 2.6.18-53.1.19.el5) in between usually contain only security fixes (please note my usage of "usually" :-)). So I find it very likely that a module version compiled for one -8.1.x kernel will work on all other -8.1.x kernels and less likely to work on a 53.1.x one. Based on this assumption, keeping one kernel module for each major update and using weak-updates for the minor updates would probably work in a large percentage of cases.
For CentOS in particular, I can see that older kernels are actually not available anymore on mirrors, neither as separate packages nor as part of ISO images. The only way that I can think of to get those older kernels is to install from ISO images written some time ago on physical CD/DVDs - but these ISO images are only released for major updates, so only one kernel version per major update is actually available for those who choose this installation method and don't want to update to the latest and greatest. For this case, again, having one kernel module for each major update seems to be enough.
Disclaimer: I don't have any connection to Red Hat and I'm not a CentOS developer.