Mobo Compatability

[Aleksandar Milivojevic]

Michael A. Peters wrote:
> If I'm not mistaken, most SATA raid chips are really a psudo software  
> raid, done with the driver - and will never be as good as true hardware  
> raid.
> 
> IE if you want raid, use a real raid controller, like what 3Ware offers  
> (or a SCSI raid controller)
> 
> If software raid is good enough, use the kernel software raid rather  
> than a kludge device made for marketing buzzword purposes.
> 
> Please someone correct me if my understanding of SATA raid is  incorrect.

You are perfectly correct.  90% of "RAID" SATA controllers are not 
really RAID controllers (make this 99% of "RAID" SATA controllers built 
in motherboards).  RAID on them is done in software once the OS boots. 
As you said, it's just marketing buzzword.  The only reason they exist 
is to enable peple running home/professional version of MS Windows 
operating systems to have software RAID devices (native Windows software 
RAID is enabled only in server versions of Windows).  On Linux (and all 
other decent and even half-decent operating systems), you don't need 
them.  Just turn off "RAID" in BIOS, and you'll be fine.  There is also 
small percentage of "accelerated" RAID controllers.  Those are also done 
in software (special device driver needed, and often not available for 
Linux) with controller having some accelerating features.  In 
real-world, good pure software RAID solutions (as the one built in 
Linux) were often much faster than those "accelerated" controllers.

My advice, either make sure board has *real* hardware RAID controller 
(not accelerated software RAID, but real hardware RAID), or turn off the 
software RAID in BIOS and use Linux md driver to make Linux native 
software RAID.  I've been using Linux native software RAID for long time 
on both "old" ATA and newer SATA disks, and in both cases it works great.

-- 
Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
Systems Administrator                           1499 Buffalo Place
Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7