Re: Motherboard RAID1
On Sat, Jan 05, 2008 at 10:18:36PM -0500, Felix Miata wrote:
> I booted the 5.0.1 CD just to take a Knoppix look at a system with WinXP
> installed on motherboard HPT RAID1, but with several partitions on each,
> including ext2 and ext3. What I see in fstab is perplexing. There are
> discrete entries for each partition on each of the two disks as in a normal
> non-RAID system, yet, instead of each of the partitions being parts of hde
> and hdg as the init messages indicate to expect, they're all device mapper
> entries. What's the story? Can Knoppix access these two disks as one? If so,
> how? I don't see anything about RAID or fstab configuration in the Knoppix
> KDE Menu.
It looks like you have a "softraid" controller. Real hardware-raid
should just show the disk configuration that has been configured in the
adapters settings, regardless of the operating system, and there is no
way to access individual disks.
Softraid instead requires a (small) driver from the OS side, which is
in this case the device mapper via the "dmraid" command on Linux, in
order to give a raid-view on the data.
If Debian/Knoppix shows dmraid entries in /etc/fstab, and still has a
device file for each physical partition in /dev, then everything looks
OK to me. It is a typical softraid configuration. Mounting of the raw
partitions should NOT be possible, they only show up in "dmesg" before
dmraid -y is being run and hides them in favour of the mapped
partitions.
Not to confuse with "software raid", which would mean that ONLY the
operating system has control over the way data is spread across the
disks. This is also supported by Linux, but not yet used by default in
Knoppix because in case of a misconfiguration in the users device
settings, data could be destroyed if disks are mounted read-write.
Regards
-Klaus Knopper
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