[ILUG] Highpoint Sata RAID

[Paul Jakma]

On Wed, 23 Mar 2005, Niall O Broin wrote:

> Hardware assisted RAID maybe? But still, host drivers needed. Let 
> me modify my definition of hardware RAID then - hardware RAID is 
> where the operating system has NO involvment in doing the actual 
> RAID work (it will of course have to have drivers for the card) and 
> the OS sees as disks only the RAID volumes provided by the 
> controller, no matter what the physical disk layout is.

It's as good as hardware RAID. The performance sensitive stuff is the 
bus copy (pure soft RAID needs more bus bandwidth) and any ECC (XOR 
for RAID-5 usually, afaik). If that performance sensitive stuff is on 
the card, who cares whether management is done on a card CPU or a 
host CPU? Same difference performance wise (and i'd rather have it in 
my OS where it'll get broader testing).

> So you can use the not very well tested Promise Linux driver (if 
> there is one for that card) or md without hardware assistance. I 
> know which I'd use.

Indeed, but MD will gain support for offload in time.

Wasn't arguing for the use of some weird oddball RAID driver. Just 
pointing out the promise SX4 /hardware/ is very interesting, and as 
good as hardware raid (even if linux MD doesnt yet make use of it).

regards,
-- 
Paul Jakma	paul at clubi.ie	paul at jakma.org	Key ID: 64A2FF6A
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