[Nottingham] Big biiig problem regarding IDE-RAID

Rob Andrews nottingham at mailman.lug.org.uk
Tue Jul 15 13:51:00 2003

[15-Jul-2003 13:26.53 (BST) / Graeme Fowler]
 > Googling around we eventually found a thread which had hundreds of "IDE RAID, 
 > Promise card, install fails" entries... followed by a single "try the Fastrak 
 > 2000TX driver" entry. Boom! That driver not only supports all the cards, it 
 > goes through RH8 and 9 (as well as some slightly more esoteric OSes).

You may be aware that the majority of the low-end IDE RAID chipsets
(HighPoint, Promise, etc) are not real RAID chipsets at all. They have their
own RAID format for checksumming and suchlike, but the implementation is
purely done in software - both from a Linux and Windows driver perspective.
The only difference being that the BIOS implements a fair amount of the
software RAID in order to install and boot from the array.

Linux has a certain amount of support for the per-vendor software RAID, but
the controller is most useful to Linux itself without the vendor s/ware
RAID, given it's own md software RAID is very heavily optimised.

There are a few vendors churning out proper hardware IDE RAID. Adaptec have
one. You may see it on Scan - the 30-quid Adaptec is sofware, the 300-quid
Adaptec is hardware. This being because for it to be proper RAID, it needs
to be intelligent and thus requires a microcontroller (usually an i960) and
RAM, and hence the heavy price tag on these cards.

But as far as I'd be concerned... I'd have used Linux's own software RAID
instead of a vendor's binary-only software RAID module.