I agree that it could lead to unsupported systems. The mere fact that I have included things not in the base distribution, could be said about ANY system that runs anything except "basically" anything except Apache, Sendmail,PHP, MySQL, Perl...etc...

You see I am charged with getting the most reliability AND performance out of systems in the category I work with. Yes customizing everything would be bad... but I start with a Vanilla Kernel for one reason to track the changes I make to it... I DO NOT know where the RedHat Kernel Series is typically at ANY given point, I look at alot of thier mods and add some into mine. If a feature that I need they do not provide, I put it in.

On the other hand, the umount bug in the 2.4.2 and 2.4.3 RedHat kernels REALLY sucked tremendously. I even filled out a bugzilla report. They had a Custom Kernel for me. Eventually a revised kernel came out in the Errata. But alnog time after I needed a fix. I D/L'd the 2.4.7 source, massaged it, looked at the fixes they provided for 2.4.3-custom, made sure similar if not exact same changes were there. Added in the support for "RedHat" Centric items I use, added in the ones I need... recompiled. System is STILL running that Kernel to this day. Been restarted 3 times since then, once due to a drive failure. This machine runs as an extremely busy Squid Server and as a Webserver with docroot on a Netware file server.

As for Oracle, Oracle themselves officially reccomend a modified Kernel to meet thier needs in a busy machine. I also know that IBM also does the same for DB2.

Cutom kernels abound in the commercial environment also. HP-UX and SAM allow changing intricate kernel settings at compile time. IBM and AIX also have a SMIT plugin for it too. Sun does this too, as well. Compaq also is in that realm with Sysman. So for being unsupported, I'd take bets on that not being the case, even with RedHat.

I guess you read things a bit wrong from me. I basically have the Super Best fully uptodate RedHat distro with all Errata installed where relevant (packages not installed wouldn't need updating), now the differences I have that matter that are "different" from default are:

1) Kernel being patched/altered from Vanilla to start from a widely known reference
2) Additional device support added to that kernel using those patches/additions
3) Additoinal binary/program support for those devices added to the kernel

Now, my build process is very different from most, I am guessing from what I read here from multiple people/posts. I run these machines though the wringer (literally) to weed out any problems. I burn things in using the build I did with it. Then remove the burn-in progs/scripts. I then go through a checking process to make sure everything's working as expected, before I turn it over to developers.

I also differentiate between Play-Things, Development and Production. Each has it's things I'll do with them, just that Dev and Prod are more conservative.

So Mister Whysall.. stick that in your RedHat!!! ;)