I have a Dell Dimension 8400 (32-bit) that I'm going to wipe clean and install Slackware 13.37 on it.

I've been thinking about RAID for some time (as in, I bought a second drive a couple of years ago for this box but never have used it). Looking at the BIOS settings I can use

• RAID autodetect AHCI (RAID is signed drives otherwise AHCI)
• RAID autodetect ATA (RAID is signed drives otherwise ATA)
• RAID (SATA configured for RAID on every boot)

Huh?

What I've got are two SATA drives, same size (different manufacturers if that matters).

I'm wondering: do I choose one of the settings in the BIOS (nice to know which would be the best choice) or do I do a software RAID setup or some combination of both? Any hints? Any sage advice?

Thanks.

i prefere Linux software RAID, i stay completely away from dump SATA-RAID controllers. I've seen several SATA-RAID controllers loosing configuration or roasting a complete RAID, so SATA-RAID is no option for me.

Linux software RAID is available for more than 10 years, so it will work well, stable and i am able to repair it without requiring vendor specific management tools. All is available as a part of the OS and i am able to transfer a complete set of Linux software RAID disks to another host without loosing any byte.

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You have very little flexibility with the BIOS method. If you use one of the Linux (ie soft) raid methods, you can do something like this :

Assume you have 2 x 1 TB disks

/ on mirror of say 1st 20 GB
/home on (separate) mirror of say (100 GB) or more
/movies on simple stripe of 2 disks - rest of disk.

Obviously a crashed disk will lose all your movies - but that's not really critical data.

Later on, you can upgrade to bigger capacity disks with far more ease (if Linux soft raid)

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Software RAID is probably your only reasonable choice. Most if not all of SATA RAID controllers that come on motherboards are complete junk. Unless you've shelled out some serious cash for a good PCIe or PCI-X SATA RAID controller stay away from the "hardware RAID"[0] that you have. Since you have different drives from different manufacturers, they probably aren't the same size (sure, they'll say 500GB but one may be 495 GB and the other 480GB). That may cause hell if you even attempt to use the crap-raid controller you have. mdadm has no such problems however.

I suggest you read README_RAID.TXT on your install CD or a mirror thoroughly before you get started, then refer to it throughout the installation as it will make your life much easier.

[0] Most of these are completely fake and rely on OS drivers to do everything for them. That means that they are software RAID with less testing, lower performance, and decreased reliability when compared to the tried and true Linux software RAID.

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As the others have said software RAID is the best way to go. I found it very easy to set up on Slackware, by following the README. With two disks RAID1 is the best option - you get the benefit of redundancy and faster read speeds as well, at the cost of slower write speeds. But as Mark has said, you could go with software RAID0 on a partition which wasn't too important, and could be reinstalled - /usr, for example. If you intend to use a /boot partition it needs to be on RAID1.
Before setting RAID and LVM up on real physical disks I tried it all out in virtual machines first, creating two virtual disks. I took notes and then installed RAID and LVM on the physical disks. It was very easy to do.

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All righty then -- software RAID is the way to go (don't know diddly about the controllers, don't know if they're worth a hoot, don't really want to know all that badly, so... to heck with those).

Thanks to all for the input.