hardware mirrors recognized as individual disks in fbsd

Apatewna apatewna at yahoo.gr
Tue Jan 23 17:26:57 UTC 2007

> On Mon, Jan 22, 2007 at 07:16:59PM -0600, Damian Wiest wrote:
>>> Forging ahead, I get ready to start playing the mounting game, but
>>> lo-and-behold, suddenly I have 4 disks whereas in windows I had two.  Now I
>>> praise FreeBSD for it's superior intellect here, but now I have a problem.
>>> I want two 160GB mirrored volumes, not 4 unmirrored ones.  The RAID is an
>>> ASUS P5DR1-VM motherboard with a ULI raid chipset onboard.  Very nice setup
>>> for the money.
>>> Is this normal?  Am I going to break my mirror if I mount a single disk?  If
>>> so, how do I mount a mirror?

I have a Gigabyte motherboard GA-7N400Pro2 with an onboard IDE RAID 
controller IT8212F.
Two IDE disks of 80GB connected on it. I have created a RADI-1 volume 
using the onboard RAID utility and partitioned the volume (50-50) while 
installing windows. In windows I could see two primary partitions.

When I installed FreeBSD 6.1, sysinstall gave me the option of 
installing on three different disks.
The "ad0", "ad1" and "ar0". The last is the RAID-1 volume that FreeBSD 
recognises by default. I chose "ar0" and proceeded to install into the 
second partition of the volume. All well so far.

I chose to install Gnome 2.16 from Tinderbox which brought HAL along the 
way. When I booted the Gnome desktop, I saw a sum of six partitions, 
thanks to HAL not separating/hiding the drives that the RAID-1 volume 
consists of (a known issue). Maybe this is what you see?

I also wonder, since I have never had a true PCI RAID controller 
together with FreeBSD, if every RAID volume behaves like this. I am 
familiar with the term "soft-raid controller" and clarifying, it means 
that it is half implemented as hardware, and half as software (something 
like win-modems). That's why FreeBSD sees the detailed "interior" of the 
array - the driver can control the whole RAID process, add/remove member 
disks and so on. I could be wrong about this, gotta get some hardware to 

Thanasis Rizoulis
Electronic Computing Systems Engineer

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