Liam Marshall lsrpm at mts.net
Tue Sep 21 00:51:52 UTC 2004

Chris Kacoroski wrote:

> Liam,
> I did several tests with SATA and SCSI and found out that the 
> controller card is a limiting factor.  The fundamental difference 
> between the two technologies is that SCSI drives queue up the requests 
> and the optimize the path of the r/w head across the disk.  SATA do 
> not have this ability so the r/w head wanders all over the disk 
> handling the requests in a first come, first serve basis.
> What this means, is that if you are reading or writing one large file, 
> SATA perform as good as SCSI (if they have the same spindle speed).  
> If you have several different processes r/w to multiple files on disk, 
> SCSI out performs SATA by a large margin.  The new SATA standard out 
> sometime next year is suppose to include queueing, but until then SCSI 
> is definitely worth it for small installations like yours.
> If you have a large installation (e.g. 2TB+ of disk), you can use a 
> device like the EonStor raid which connects SATA disks to a scsi 
> controller and performs very well.  I have one of these and plan to 
> get another one for a different application.  I tried 3ware cards, but 
> they failed in my application (I still use them to mirror the system 
> disks and they work great for that).
> cheers,
> ski
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

I was thinking sata raid because the mb I am buying has a sata raid 
controller on board

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