another newbie question

[Jeffrey Watts]

On Fri, 20 Oct 2000, Tony Hammitt wrote:

> This is getting kind of silly.  You can't buy an RS/6000 server (or
> whatever they are calling them now) with just one PCI bus.

Hold on, we're talking about RAID for low-end servers, priced in the
$2k-$3k range.  Maybe we've diverged a bit, but this is where this
discussion came from.

> You can get 32 independant PCI buses on an IBM S80.  It is quite
> possible to double the throughput of an RS/6000 just by rearranging
> the disks, I've done it myself.  I'm sure that Sun, SGI, HP and Compaq
> have the same thing.

Actually, on real equipment, PCI is not used.  Not enough bandwidth.  On
SGI Origins, the PCI bus is an add-on and hangs off of the XIO bus, which
has some obscene bandwidth like 1.6GB/s (or was it 3.2GB/s?).  But your
point is valid.

> My $180 PC motherboard has two PCI buses.  Any new mid-range server
> has a better motherboard than that, I'd hope.

Yours does?  My not-so-state-of-the-art PC motherboard has only one, with
the USB controller, both PCI controllers, and both SCSI controllers all
hanging off of it.  It's a Tyan Thunder II dual Pentium 333 board (low-end
server-class board).

> The state of the art has moved on from just one bus per computer. It
> did so a long time ago.

Well, I wasn't aware that newer motherboards had two PCI controllers.  
Looking at some sites, I see no mention of dual PCI busses, and neither
the 440GX or 810e intel chipsets list dual controllers.

http://developer.intel.com/design/chipsets/440gx/index.htm?iid=PCG+devleftnav&
http://developer.intel.com/design/chipsets/810/810e.htm?iid=PCG+devleftnav&

What motherboard are you using?

> There is no point in discussing this further.

Well, I actually see it as a very germane discussion, because a lot of
folks have to make these kinds of purchasing decisions.  I think it's
probably very illuminating for them, since both of us appear to have a lot
of experience with RAID.

My statement is that an inexpensive RAID card will deliver superior
performance over software RAID in most situations, on PC-class hardware.  
You assert the opposite.  I think it is useful to put our numbers down and
compare, because I certainly would like to know if my conclusions are
misinformed.

Thanks,
Jeffrey.

o-----------------------------------o
| Jeffrey Watts                     |
| watts at jayhawks.net         o-----------------------------------------o
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| Sprint Communications      |  at thee..."                            |
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