🚀 go-pugleaf

George Bell <MasterofTimeADim@netscape.net> wrote:
>Floyd Davidson wrote:
>> 
>> Mine were not exactly expensive...  I watched ebay for awhile, and bought
>> used 9mb SCSI2 lvd drives.  Something like $30 each...
>
>But don't you need a special SCSI raid controller and aren't they real 

The Tyan S2462UNG motherboard has dual SCSI2 LVD controllers on
board, and that works just fine with the Linux software raid.

>expensive?  I saw one at a website for about $500.  Can you somehow 
>implement raid 5 with more than one ordinary SCSI controller(As you can 
>see I'm a newbie when it comes to SCSI, and I'm thinking of trying it out).

Yep, and it isn't even really very hard either, though booting
from a RAID array is a bit complex.

Two controllers are better than one, but even with just one
you'll get some improvement.  I don't remember the specifics,
but basically for an individual motherboard, you want enough
SCSI controllers to be able to flood the PCI bus.  Then you want
to put enough hard disks on each SCSI controller to be able to
flood each SCSI bus .  

For example, if the SCSI bus will do 80Mb/s max there is no
point in putting 4 80Mb/s drives on it!  But 2 40Mb/s drives or
4 20Mb/s drives will show a significant improvement over just
one, and the results will be the same as an 80Mb/s drive.

You want to find out what kind of bandwidth your motherboard can
deal with, and then choose controllers to match.  Then choose
disks.

-- 
Floyd L. Davidson         <http://www.ptialaska.net/~floyd>
Ukpeagvik (Barrow, Alaska)                 floyd@barrow.com