[K12OSN] SATA vs SCSI

[Les Mikesell]

On Mon, 2004-09-20 at 19:51, Liam Marshall wrote:
> >
> fair enough, I like the idea of scsi anyway,   I don;t have a raid 
> controller for the scsi, but I have an Adaptec controller with two 
> connections, I forget off hand which model it is.  It does the ultra 2 
> wide and the narrower type.  In order to do Raid, of whatever flavour, 
> you need either a raid controller or 2 scsi cards, right?  the one I 
> have is not a raid controller

You can run up to 15 SCSI drives on one controller - even on the
same cable.  You just have to make sure the drive select settings
don't conflict.  Unlike IDE, the controller will overlap commands
to all the drives but you probably start to run out of bandwidth
with about 4 active drives (depending on the controller and drives).
Anyway, software raid works fine on scsi, especially raid 1 mirroring
which takes next to no cpu work although it uses the most disk
space.  A nice side effect is that you can clone a machine by
breaking the mirrored set and moving one, and you can access the
data by moving a drive to any machine with a normal controller.

---
  Les Mikesell
    les at futuresource.com