Actually, the 3ware escalade cards are really kinda cool in this respect.
Each port on the card gets it's own controller so you're not sharing
controllers with pairs of devices, and the card handles almost all other
processing itself, so the CPU impact on your system is very small.  In
fact, as far as linux is concerned, the mirror (or raid on a larger
card) just looks like a SCSI device.

Jeff


On Wed, 15 Aug 2001, Mike Hicks wrote:

> <jeffr at odeon.net> wrote:
> > 
> > Re: #1: Question is irrelevant.  It doesn't matter why Yaron needs 75
> > gigs of storage space.  "Because" is a perfectly valid answer.
> > 
> > Re: #2: Escalade 6200 (2-port) card:	$ 120
> > 	75GB IDE (x2):			$ 412
> > 					-----
> > 	75GB IDE mirror			$ 532
> > 
> > 	73GB SCSI (x1):			$ 535
> 
> Of course, the amount of time your CPU spends waiting for the non-threaded
> IDE subsystem to work might be worth the money.
> 
> This may be comparing apples to oranges, but I once managed to get my SCSI
> CD-RW to rip audio CDs (it doesn't like grip for some reason *sigh*), and
> the performanec impact on my system from the ripping was barely
> noticeable.  Doing the same on my UDMA DVD-ROM drive completely tanks the
> system, and suddenly things take several times longer than they did before
> (I/O-bound operations are the worst).
> 
>