First thing: read the howto.
I set up software raid 0 on a fresh Slackware install, on 2 Western Digital Raptor hard drives (SATA) with a Promise SATA Raid controller.
I ran into a few problems, but I got it all figured out and now it all works great.
First thing I did was boot slackware, and chose a kernel from the CD. I chose 'sata.i' because my controller _needed_ it just to see the disks. If it didn't I probably would have chosen one of the RAID kernels, but I seemed to get by fine.
After you pick your kernel you need to do your partitioning. I used fdisk on both disks, and made my partitions look like so:
Code:
Disk 1
/boot - 32M - P. Type 83 - Linux
/ - 35000M - P. Type FD - Linux RAID Automount
SWAP - 512M - P. Type 82 - Linux Swap
Disk 2
/boot - 32M - P. Type 83 - Linux (this partition does nothing on my system).
/ - 35000M - P. Type FD - Linux RAID Automount
SWAP - 512M - P. Type 82 - Linux Swap
Make sure you set your RAID partitions to type 'fd' with the 't' tool of fdisk.
After making the partitions I made a simple /etc/raidtab file, that I got right from the HOWTO. It worked great, and I started up my RAID array with: raidstart /dev/md0 (you're array will probably be called mdx, where x is 0, 1, 2, etc...
Raidstart worked, so it was time to start the Slackware setup tool. I set up my swap drives (I didnt do RAID on them, but I could have now that I think about it), and then formatted my RAID array with ext3. After this I chose packages, installed, chose the same kernel (sata.i), and ran lilo. It all worked (after a LOT of coffee and hours wasted) and I booted my new RAID 0 system. Later on I grabbed a new kernel (latest 2.6), compiled it and after some tweaking got that working too.