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RAID Questions

I am a RAID newb.

I have a brand-new Dell Precision T1500 workstation with two 700GB SATA drives, pre-loaded with Windows 7.

Of course, Win7 has already been wiped off.

My goal is to have a redundant Debian (Stable) system, such that the second drive is a mirror of the first drive. I would think RAID1 would be the route to go.

However, being a RAID newbie, I'm running into all sorts of problems, not least of which that I simply don't understand some of the basic concepts.

I thought there was HARDWARE RAID and SOFTWARE RAID. Not knowing anything about it, I would have thought that with HARDWARE RAID, you'd go into the BIOS of the special drive-controller hardware (Ctrl-I in this case, just after the POST), and tell the hardware to mirror this drive to that drive, and that then when you go into the installation of the OS (Debian, in this case), the OS's partitioner would see one drive (the main one) and not see the other one, because the hardware RAID controller would "hide" it. Or if the OS partitioner saw the drive, it would see it as a clone/mirror of the first. At any rate, I thought the OS installation would be essentially uninvolved in the RAID setup.

I thought that with SOFTWARE RAID, all the RAID stuff would be done in the OS, and there'd be no need for a hardware controller.

But apparently this RAID hardware controller (Intel Rapid Storage Technology - Option ROM - is some sort of hybrid FIRMWARE RAID system.

It has three RAID levels available in the controller BIOS screen - RAID0, RAID1, and RECOVERY. I've been unable to find any reference on Intel's web site (or Google generally) for an explanation of this RECOVERY level. My best guess is that it is RAID10 (RAID1+0 ?) and Intel can't be bothered to be consistent in what it calls things.

If I set up the controller's BIOS screen to either RAID1 or RECOVERY, when I start the Debian installer and get to the partitioning scheme, I see a single 700GB RAID partition with a 1MB unusable partition, and then the /dev/sda and /dev/sdb drives.

If I try to partition the /dev/sda drive, it warns that all the RAID information will be wiped out. If I leave that alone and try to partition the RAID partition, I have no option to create separate partitions and just have one huge partition that I can mount on / (or wherever).

If I set up the controller's BIOS screen to non-RAID for the drives, and then use only the installer's partitioner to manually setup all my partitions on both drives, making them identical, and then use the RAID option in the partitioner to create a RAID partition for each actual partition and set mount points, the installer continues, but then won't install grub or lilo. (Further, I can't toggle the bootable flag on the drive's first partition; it stays OFF no matter what. This may be a bug in the installer - I found similar references via Google, but could not understand the "solution" (or even if there really was a solution).) But I figured I might could fix that later, and went ahead and rebooted. Of course, the system didn't boot, so I used the installer CD to boot into recovery mode, and then mounted a partition or two, and as far as I can tell, the partitions are completely blank, even after what seemed to be a successful install (minus the boot loader problem).

In short, I have no idea what I'm doing, or how to do it.

Should I use RAID at all, or should I use some other cloning technique, perhaps dd or rsync from a periodic cron job? (I was able to successfully install/boot a complete Stable system with RAID off in the firmware BIOS, installing onto the first drive like it was the only drive in the system.)

If I use RAID, do I set the Intel Rapid Storage Technology BIOS options to RAID1, RECOVERY, or no RAID?

How do I get around the problems I'm seeing in the Debian paritioner (no bootable flag, can't create multiple partitions or partitions are empty after install)?

Thanks for any suggestions/hints/clues.

Kent West<*)))><
Praise Yah! \o/

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