I’m in the process of building up a SAN from scratch using SCST & CentOS. I’ve played around w/ kernels in the past but hadn’t done it in a while. When downloading from Kernel.org recently I couldn’t get a bootable kernel no matter what I did w/ CentOS (and yes, I did load the CentOS .config file into menuconfig before compiling my kernel.)

  Come to find out, because CentOS is using a modified 2.6.18 kernel that little .config file is very out dated. As of kernel 2.6.31 a new kernel parameter is available called “enable deprecated sysfs features to support old userspace tools” which is under the General setup area. Once I enabled that option, I was good to go. It has something to do with why my SAS RAID card wasn’t getting picked up upon boot up. Everything else after that was a piece of cake!

You could have also just added this to your .config file. (NOTE: Hats off to Vanecka!)

Couple Kernel compile links for CentOS 5:

http://wiki.centos.org/HowTos/Custom_Kernel  (official CentOS wiki kernel build page)
http://www.howtoforge.com/kernel_compilation_centos_p2  (HowtoForge article)
http://kerneltrap.org/node/1783 (Old kernel trap article which mentions the use of -j8 for make parameters so you’ll use all of your cores on compiles! I did a ‘make -j8 all’ and finished my kernel compile in under 5 minutes on a Xenon E5620 CPU!)
http://www.linuxfromscratch.org/lfs/view/6.4/chapter08/kernel.html (LFS link on kernel compile)