CentOS - May 2006 - CentOS 4 and SATA RAID

There have been several threads about SATA in the past weeks and the 
problems with it. I'm still not clear, though, if SATA in general is a 
problem or just specific functionality or hardware.
Do I understand correctly that "mainboard built-in" SATA RAID is a
nono on
CentOS? That I would need a third-party RAID card for this? What about 
SATA non-RAID or SATA2? Is SATA supposed to work in general or do the 
disks need to run in IDE mode? Do I generally need drivers from the 
hardware (mainboard, chipset) vendor or is "normal" SATA supposed to
work
with the packaged drivers?


Kai

Kai Schaetzl wrote:
> There have been several threads about SATA in the past weeks and the 
> problems with it. I'm still not clear, though, if SATA in general is a 
> problem or just specific functionality or hardware.
specific hardware.
> Do I understand correctly that "mainboard built-in" SATA RAID is
a nono on
> CentOS? That I would need a third-party RAID card for this? What about 
> SATA non-RAID or SATA2? Is SATA supposed to work in general or do the 
> disks need to run in IDE mode? Do I generally need drivers from the 
> hardware (mainboard, chipset) vendor or is "normal" SATA supposed
to work
> with the packaged drivers?
> 
there is no such thing as sata support, as a blanket cover. you need to
make sure that the specific chipset / controller is supported ( sort of
like Scsi works ).

- KB

-- 
Karanbir Singh : http://www.karan.org/ : 2522219 at icq

On Fri, May 19, 2006 at 02:31:17PM +0200, Kai Schaetzl enlightened
us:
> There have been several threads about SATA in the past weeks and the 
> problems with it. I'm still not clear, though, if SATA in general is a 
> problem or just specific functionality or hardware.
> Do I understand correctly that "mainboard built-in" SATA RAID is
a nono on
> CentOS? That I would need a third-party RAID card for this? What about 
> SATA non-RAID or SATA2? Is SATA supposed to work in general or do the 
> disks need to run in IDE mode? Do I generally need drivers from the 
> hardware (mainboard, chipset) vendor or is "normal" SATA supposed
to work
> with the packaged drivers?
> 
It really depends on your motherboard/chipset. I have several motherboards
where the onboard SATA works just fine. Disks show up as a scsi disk.

The "Onboard RAID" really isn't onboard, just a few extra hooks
into the
BIOS that software drivers can use. This is necessary for Windows since
there is no true software RAID support, so they came up with this
half-cooked idea. It is possible to use these Pseudo-RAID devices with the
latest device mapper (dm) code in Linux, but generally speaking it's more
effective and stable to just use the built-in software RAID. If you are
dual-booting a machine, then you might look at the dm option. Hardware RAID
is definitely easier. A 2 port 3ware 8006-2LP should only run about $130 US,
and a 4 port 9550sx-4LP is in the $250 range. 

Some of the latest boards need extra drivers to work in older kernels. I
expect RH patches those in as best they can, but there may still be some
lag. 

Matt

-- 
Matt Hyclak
Department of Mathematics 
Department of Social Work
Ohio University
(740) 593-1263