Partitioning a RAID 0

[smolloy]

Hi Guys,
I've googled around on this question and am a little clearer on it, but I would really appreciate your input.

I'd like to set up my two 250GB hdds as a RAID 0 through the hardware RAID on my motherboard (link). I don't plan on having any other drives on this system (apart from a removable drive for backup purposes).

I'd like to be able to partition this for multiple OS's (suse, XP, and an extra partition for experimenting with new distros), as well as a separate /home, /usr, etc. for each OS.

My question is, is it possible to partition a RAID 0 in this way, as if it is just one big drive?

[bigtomrodney]

I don't think that's actually a hardware RAID, most RAID controllers support RAID but it's really only facilitating software RAID. It's pretty confusing. Genuine RAID controllers are expensive and have their own RAM. If it is a genuine RAID controller your operating systems shouldn't even be aware that it is a RAID, so partition as you would normally. If you find it isn't genuine hardware RAID you will need to boot linux from a seperate disk or from a partition which is not part of the stripe. If it is software managed linux support isn't as good as just using the kernels own striping, and you will also have to contend with Windows drivers.

[smolloy]

It's pretty confusing.

That's for sure!

Here's a quote from the motherboard manual,

The motherboard includes a high performance RAID controller intergrated in the NVIDIA nForce 590 SLI southbridge chipset. It supports RAID 0, RAID 1, RAID 0+1, RAID 5 and JBOD for four independent Serial ATA channels.

It then goes on to explain how to set the RAID in BIOS, and how to use the "NVIDIA MediaShield Utility" by pressing <F10> during boot.

Does this not sound like a hardware RAID controller?

[smolloy]

Apologies bigtom but it seems you were right. I did a bit of googling and it looks like it is fake RAID.

I found the following about my motherboard on one forum,

> Board is an Asus M2N-SLI Deluxe (AM2), says it has hardware raid
> (Raid0,raid1, raid0+1, raid 5, and JBOD via the onboard NVIDIA
> MediaShield RAID controller. This sounds like hardware raid to me and
> is configured via the bios menus.

It is fake raid. It is not hardware raid. At best it may have an xor engine in the chipset that the driver/bios can use to reduce the cpu load. Marketing people think anything done in the bios makes it hardware. They would claim a winmodem is entirely a hardware modem too.

I also found this,

*Real* hardware raid doesnt need an OS layer / driver to work.
This kind of raid relies on the BIOS *and* on a Windows driver.
It is more a raid feature enabled in the BIOS and managed by the Windows driver.
Linux can or not support this BIOS feature depending of the chipset.

So now I will set it up as a RAID 0, hoping that suse 10.1 has the drivers to recognise it as a RAID. If not, I'm just shafted and will just use them as separate drives (or maybe LVM). If it does recognise it as RAID, then I will partition it up for linux and windows.

My question is now, will using a software RAID as a dual boot system (XP, suse) work, or does the software implementation of RAID happen in such a different way between the OS's that there is no chance this will work?

Thanks for your help guys.

[smolloy]

Started the SUSE install and it bombed. I got a warning (thankfully very close to the beginning of the installation process) that the BIOS was reporting a RAID that was actually a software RAID and that bad things would happen if I continued.

I read elsewhere of someone who received the same error message after successfully using his pseudo-RAID system with FC5, so I'm currently burning the disks to try that out. I'll let you know how I get on.