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Sjaaksken 09-11-2006 12:49 PM

linux installation on dual boot software raid

I have been using linux for several years now but recently I assembled a new pc and I want to install opensuse on it.

I have a 64 bit amd processor, m2n32-sli deluxe mainboard (Ausus), three identical seagate SATA hard drives in a raid 5 configuration (software nvidia controller) and windows XP installed.

I have partitioned the raid 5 array in three partitions: one ntfs with windows, one reiserFS for opensuse and a swap.

Upon boot the installation programs starts but during disk setup I get an error message:


one or more disks have been detected in a software raid setup
And offcourse it shows my three seagate disks being part of the raid5: hda hdb hdc

It displays a warning that all data on the raid 5 will be lost and the array will be deleted if the system is installed on one of these drives.

Offcourse this is not the idea, the idea is to keep the raid 5 as one big disk with three partitions and have dual boot windowsXP and opensuse.

How can I get to the installation with raid 5 support? The software raid 5 controller is made by nvidia. Any help is appreciated.

ramram29 09-11-2006 03:11 PM

The Software BIOS RAID setup for Windows does not work for Linux. You will need to disable Software RAID in the BIOS in order for mdadm to work. However, if you do that then Windows software RAID may not work or you may need to get a Windows driver that works without the BIOS setting. It may make your Windows setup run a little slower but then both OSes will be able to run their own software RAID. The BIOS RAID setting allows a chip to copy from one disk to the other taking less resources from the main CPU. This is one reason why I prefer hardware RAID especially on heavy-hit servers.

Sjaaksken 09-11-2006 03:59 PM

Changing the raid settings in the bios won't change my current data? Is there a good howto for installing on raid drives because I tend not to really get what Im supposed to do with this raid setup, and it's very important to keep my current data intact..

Sjaaksken 09-11-2006 09:18 PM

I actually don't get the silence around this subject. It appears to me that lots of new mainboards support software raids and alot of users are running dual boot systems. It strikes me that it is currently such a non-issue, I have searched on all the regular places and apparently everyone just assumes it is possible to erase your complete raid array. THIS IS NOT THE CASE. Software raids will be everywhere once the newer mainboards become standard and there will be alot of demand for installing linux on such drives.

I have installed windows xp with a raid floppy, isn't there a way to do the same for linux? Or isn't it possible to wrap the driver into the kernel like ndiswrapper does for wireless network cards?

I wanna get linux set up soon but am not in the possibility to erase my drive, so any help is appreciated.

ramram29 09-12-2006 01:12 AM

First, before you try anything make sure you have a good backup of your data and also make sure you test that the backup works and that you are able to restore it.

Most $99 motherboards today specify RAID capability but in reality they do very little. Some of them contain a chip that processes the copying from one disk to the other. However, most of the I/O is still done by the main CPU. So you are gaining very little CPU load.

These motherboards are made so that you have to install a Windows driver in order for Windows to recognize the chip that does the copying. However, don't let this fool you. These motherboards are not native RAID. They do help increase I/O and CPU but very little; compared with the $300 and up native RAID controllers.

The Linux kernel does not bother with creating modules for these low-end software RAID chips. Linux software RAID uses the main CPU and I/O. The logic is that if you are going to spend $400 or more on three disks for RAID5 then it would be wise to spend the same on a good RAID controller.

You will need to disable the RAID BIOS settings in order to ge it to work.

Sjaaksken 09-12-2006 10:03 AM

thx for your reply.

Tho the m2n32 isnt really a 99$ mainboard, its one of asus top notch mainboards. It also contains two raid controllers, the nvidia one and a SIS controller.

Actually if you look at it I haven't spent 400$ on the raid5 setup, since raid5 uses the capacity of two disks and u loose the capacity of one disk I hardly spent 99$.

But even tho it might not be a big performance gain using raid5 (tho it works pretty smooth), the problem is I AM using it, have data on it and just cant erase the disks, I would need an extra hard disk for the backup.

I think the bottom line is:

you can't use windowsxp and linux dualboot on an fakeraid.
Actually that bothers me because its just something that will pop up more and more.

Considering what I found to be the only solution is using the nvidia mediashield manager to migrate the raid5 to a raid0 or 0+1 and get the third disk out of the array to install linux on that disk. I'm reluctant to do so since Im not willing to risk months of work and data.

Guess only option left is to get an extra hard drive just for installing linux. I wonder, is it really that hard to just recognise an nvidia raid array that you have to go to so much trouble just installing it?

ramram29 09-13-2006 02:38 PM

That's the problem with software RAID (it doesn't work on the disk block level but rather on the partition level). If you setup Windows soft RAID then only Windows will recognize it.

The same for Linux, if you set it up with soft RAID then the array will only be recognized when you boot into Linux only and after it loads of the module. You can have both Windows and Linux running on the same three disks each using their own RAID 5 configuration.

You will need to leave space on all three drives in order to fit the Linux partitions. What you can do is shrink your current partitions then install Linux and configure RAID during install or after using mdadm.

I would recommend to first save all your data to an external disk before attempting anything.

cbann 06-04-2007 07:51 PM

any luck?
did you have any success getting linux installed to an existing nvidia raid 5 array? I'm trying to do the same thing now with Fedora 7 and must keep windows intact as well...

jsm008us 06-29-2007 11:21 AM

I also created a RAID 5 using the nVidia RAID option from the motherboard (ASUS motherboard) with Win XP. I have also been told that it's pretty much impossible at this point to make a dual boot like this. I don't know about the SiI3132 RAID controller thing on some motherboards, they claim it supports Windows/Linux/Mac but I'm not sure if it's simultaneous or not.

Actually, I think Gentoo allows you to use it:
This might mean other distributions could work...

dtdionne 12-18-2007 12:17 PM

Any solutions to this yet? I've got a similar problem but different in the fact that I don't have an os installed...

jsm008us 12-18-2007 04:31 PM

I think the best solution is to either
  • Not do a software RAID (just have each OS on it's own drive)
  • OR get a RAID card ($$$) that does the RAID on-board. Check compatibility online to see how people think of it. Software RAID is too buggy to be reliable, especially on dual-boot systems.
I'm going to remove my RAID and go with the first option, since I've been having problems with NVRaid at the BIOS level. I will use one drive for Windows, one for Linux, and one shared between both

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