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Hi,
In short:
I have two RAID-1 arrays. One is BIOS managed (DDF) and the other is linux software RAID. Windows is installed on the BIOS managed one and should stay there for now. Hence I can't deactivate RAID functionality in the BIOS. Due to BIOS bugs (or "features"?) I can't get Grub to work ("Hard disk error ") when installaed to BIOS RAID disks. The BIOS can only boot from BIOS RAID arrays and CD-Roms. I installed Gag, but it sees only BIOS-RAID disks. What to do?
More detailed:
currently I've got a Windows Server 2003 running and want to replace it with arch. The System offers some software RAID (LSI, with own BIOS, I think it's some Intel ICH chip) which manages a 250Gb RAID-1 array (two disks). I got a new 500 Gb disk and installed arch on it, based on the wiki entry about a linux software RAID plus LVM setup. I chose to create several partitions, among them a separate /boot partition at the beginning of the 500 Gb drive. /boot is formatted as ext3 and a RAID-1 disk. All the other partitions, are RAID-1 partitions as well, even swap.
Basically I want to have Grub as bootloader to select between Windows (on BIOS RAID, linux can handle the format (ddf), too ) and Linux (linux software RAID, not an RAID array for BIOS). Unfortunately the BIOS only allows me to boot from RAID arrays (and CD-Rom/USB), if RAID functionality is selected. Like I said, I can't deactivate that because of Windows. Thus I installed Grub to both BIOS RAID disks MBRs. The problem: Grub greats me with a "Hard disk error" message. Different sites stated this is a problem with a buggy BIOS delivering wrong LBA information. A BIOS updade did not fix that. After that I installed Gag, which could be started. Unfortunately it sees only the BIOS RAID-disks. With the current configuration it can only chainload the windows RAID-1 array. (it just does not see the linux disk)
It wasn't possible to install GRUB to the superblock of the first partition of those 250Gb disks. Grub complained about LBA BIOS disk geometry information (Error 18). So it was not possible to get Grub (or LiLo) to run from the Windows array. This is probably because the large size of the first partition there and some BIOS LBA bug. Either I get this LBA thing fixed (the BIOS RAID manual even proudly tells it supports 48-bit LBA) or make linux run on a BIOS raid. The next thing I tried was to make the 500Gb linux hard disk into a "single drive BIOS RAID-0", at least allowed me the RAID BIOS to create such a thing of the single 250Gb disk. Now I could select it as boot device and start Grub. But then all my linux software RAID did not work anymore as the disk is seen not as its normal partitions (sdc1, stc2, ...), but as RAID device (mdraid) which can be started. I did not get it work that way, but even if I did, I would have a "double RAID" (BIOS and mdraid) for this disk. Which is probably no good things.
Now I actually ask for some advice on how to get this working. :-)
I can think of using the BIOS RAID for arch, too, but I would probably need to reinstall the arch system (would be no problem). And because of the DDF format of the BIOS RAID it should be no (big) portability issue, no?. Would a small boot partition on the Windows array circumvent LBA problems when installing Grub to it? Do you have other ideas?
Thank you in advance,
Tom
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