Re: How does RAID work with IT8212 RAID PCI card?

[Lennart Sorensen <lsorense@csclub.uwaterloo.ca>]

On Tue, Jun 13, 2006 at 05:58:45PM +0200, Christian H?rtwig wrote:
> i need some advise regarding the usage of the above kernel module. Today i 
> have plugged a PCI RAID card into my computer, IT8212 chip on it, and two 
> identical hard drives on the primary and secondary master of that controller. 
> In the controller BIOS i defined a mirror set out of those both disks and 
> booted linux afterwards.
> 
> Loading the kernel module dmesg showed that the controller was found and that 
> 2 harddiscs are attached to it.
> 
> The thing that i wonder about is, that i still can "see" both harddisks 
> independently, but i would expect to see only one harddisk at all, that 
> represents the RAID set. Udev also registers /dev/hde and /dev/hdg, but (as 
> far as i can see) no further device.
> 
> Is there anything wrong about my setup? Is this i driver issue? Or is this the 
> normal and expected behaviour and its me who doesn't "use" the module 
> properly? How to i access the RAID set instead of the two seperate disks?

Congratulations.  You have a fake raid card by the sound of it.  A
hardware raid card would have only shown one drive, while a fake raid
card expects the driver to work with the bios to find out the setup (and
handle booting), and then the driver does all the raid work in software.

It is much simpler to treat fake raid cards as just another drive
controller and use linux software raid on it.  At least then you know
how it works, and it is portable to other controllers later if needed.

Len Sorensen
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