SATA VIA RAID controller issue

[Ron]

Hello all,

I am building a Linux server and have two 300 gig SATA drives I would
like to put into a mirror. I'm using a MSI KT6V with a VIA Southbridge
VT8237 SATA RAID 0 / 1 controller. I have configured the BIOS for
mirror, and when trying to install CentOS 4.3, it still sees both
drives, not just the one. I don't really want to buy a new mainboard,
its not that important of a server.

I realize that "software" raids such as the VIA can be a problem, but I
would expect that from a stripe set, not a mirror. Since I am using a
33mhz PCI bus system, I can not install another SATA RAID controller
since they all seem to require a 66mhz speed and PCI express or above.

The only thing I can think of is to install CentOS to one of the SATA
drives, and let the Linux LVM do software mirroring to the other drive
for me.

Does anyone have any ideas how I can make the hardware do the mirror
instead of the software??

Thanks for any and all input!

Ron

[Martin Maney]

Post by Ron
I realize that "software" raids such as the VIA can be a problem, but I
would expect that from a stripe set, not a mirror. Since I am using a

Doesn't matter - because they don't do RAID at the hardware level, they
*are* just two drives on a controller.

Post by Ron
33mhz PCI bus system, I can not install another SATA RAID controller
since they all seem to require a 66mhz speed and PCI express or above.

PCI express would be a problem, but if you want to go that way I'd
expect that most of them can work at 33MHz.

Post by Ron
The only thing I can think of is to install CentOS to one of the SATA
drives, and let the Linux LVM do software mirroring to the other drive
for me.

If software RAID is good enough, I can't see any reason not to do that.
The only thing you're giving up is having RAID protect the boot process
from a drive failure. Well, and mirror the boot sectors automagically.

Post by Ron
Does anyone have any ideas how I can make the hardware do the mirror
instead of the software??

The only way it can work is if there's a Linux "driver" that works with
its BIOS-level software RAID. Since the installer didn't recogbize it,
I'd guess that there isn't, at least not in the version you're trying
to install.

Just keep in mind that cheap RAID is just some code in the BIOS that
goes away when the OS is booted and you should see clearly what it's
worth. Of course hardware RAID is just some code in a ROM, too, but it
comes with its own processor to run on... and that makes all the
difference.

[Branko Kotur]

Post by Ron
Hello all,
I am building a Linux server and have two 300 gig SATA drives I would
like to put into a mirror. I'm using a MSI KT6V with a VIA Southbridge
VT8237 SATA RAID 0 / 1 controller. I have configured the BIOS for
mirror, and when trying to install CentOS 4.3, it still sees both
drives, not just the one. I don't really want to buy a new mainboard,
its not that important of a server.

This is nothing more then a software RAID solution. It is not hardware RAID.
Your best bet is to use Linux's RAID software to manage you hard drives. I
don't know what it would be called for VIA, but it's called nvraid for nForce
boards. The only way you'll get hardware RAID is to buy an add on RAID
controller, but only the more expensive ones are hardware RAID. All the
cheaper ones are software RAID which are pretty much no better then the ones
built into a motherboard.

Post by Ron
I realize that "software" raids such as the VIA can be a problem, but I
would expect that from a stripe set, not a mirror. Since I am using a
33mhz PCI bus system, I can not install another SATA RAID controller
since they all seem to require a 66mhz speed and PCI express or above.
The only thing I can think of is to install CentOS to one of the SATA
drives, and let the Linux LVM do software mirroring to the other drive
for me.
Does anyone have any ideas how I can make the hardware do the mirror
instead of the software??
Thanks for any and all input!
Ron