[CentOS] Intel Matrix SATA RAID drivers

Fri May 27 23:33:06 UTC 2005
Mickael Maddison <mike at kamloopsbc.com>

Hello Bryan,

I can't argue with the facts; at the end of the day I've elected to
use a 3Ware 8006-2LP anyway.  Just means I have to wait a few days
before I get my system running.

Thanks!

-- 
Best regards,
 Mickael
 mailto:mike at kamloopsbc.com
 Check out my latest videos at www.MickaelMaddison.com


Friday, May 27, 2005, 2:19:02 PM, you wrote:

BJSbjsio> From: Mickael Maddison <mike at kamloopsbc.com>
>> Hello CentOS,
>> Does anyone know if there's a driver out there that'll enable CentOS
>> 4.x to use the Intel Matrix SATA RAID settings on the 915 chipsets?

BJSbjsio> All FRAID cards do is setup the RAID organization in the 16-bit Int13h
BJSbjsio> disk services.  In other words, the vendor introduces its own data
BJSbjsio> organization for RAID, instead of relying on the OS.

BJSbjsio> So there's really no such thing as a RAID driver for any FRAID card
BJSbjsio> (Fake/ Free RAID) implementation.  It's all
BJSbjsio> software RAID.  The system
BJSbjsio> directly drives the ATA channels, which means the OS uses the standard
BJSbjsio> ATA driver.

BJSbjsio> That means that the FRAID card must either:

BJSbjsio> A)  Provide the FRAID logic as a kernel module

BJSbjsio> A few do, and it's a massive binary object that
BJSbjsio> is kernel build-specific.
BJSbjsio> The FRAID logic is licensed from a 3rd party, and that 3rd party makes
BJSbjsio> all of its money from that proprietary logic, so it will never be GPL.

BJSbjsio> B)  Write a data organization/interface wrapper kernel module to Linux's
BJSbjsio> ataraid.c FRAID logic module.

BJSbjsio> The GPL/reverse engineered hptraid.c, pdcraid.c and silraid.c modules
BJSbjsio> are examples that don't work well at all, and only for a few models of
BJSbjsio> each.

BJSbjsio> C)  Write a data organziation/interface wrapper to Linux's LVM/MD
BJSbjsio> instead of the ataraid.c logic module.

BJSbjsio> This is far more ideal and higher performing, but it makes it OS-specific.
BJSbjsio> I believe this might be what the RAIDCore cards do for Linux support.

BJSbjsio> Intelligent, hardware RAID don't have to do A-C, because the RAID
BJSbjsio> logic is on-board in the firmware, driven directly by an on-board
BJSbjsio> microcontroller or ASIC.  FRAID cards use your host CPU and software.

BJSbjsio> That's why RAID are so cheap and have *0* additional hardware over
BJSbjsio> a standard ATA controller.


BJSbjsio> --
BJSbjsio> Bryan J. Smith   mailto:b.j.smith at ieee.org

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