Promise RAID-1 vs software RAID-1

[Alan Horn]

On Wed, 16 Jun 2004, Jack Howarth wrote:

>    If it is true that the Promise RAID 1 does in fact
> read partially from each drive to increase the throughput,
> does software RAID-1 do the same?
>                   Jack

Raid 1 is mirroring only. For data integrity reasons I can't see how they 
could read from any but the master mirror.

I suspect your friend is confusing with 1+0, which as you say would 
require four drives to implement.

I doubr software raid would act any differently (but I'm willing to be 
corrected here :)

I can say that the promise read performance with a two disk stripe was 
substanstially better than a single disk.

I suspsct that some of this is due to the onboard cache on the card, but I 
couldn't be too sure.

I'm not a huge fan of the promise cards, 3Ware seemto be more reliable 
from what I've found.

Cheers,

Al