On Fri, Mar 30, 2001 at 06:18:00PM +0000, Andrea wrote:
> Sorry if my reply came so late....
> 
> First let me do some clarifications:
> 
> My configuration is far simple from the one you described above.... i
> got only 4 disks(3 data ,1 parity) on 2 IDE-channels.
> 
> Now.
> 
> I tried with the script you suggested and...
> 
> 1) I'm pretty convinced that RaidFrame is not guilty.
> 2) The problem is something IDE related.:)
> 
> Now i'm wondering if it was an hardware related problem.
> 
> What kind of performance can i expect when i make simultaneous access on
> 4 disks connected to 2 IDE channel?
> 
> I'm using on-board IDE-controllers of my motherboard.
> 
> I netbooted my machine and started the following script fron nfs-root:
> 
> #!/bin/sh
> 
> for i in 0 1 2 3
> do
>         dd if=/dev/rwd${i}e of=/dev/null bs=1m count=5000 &
> done
> 
> the result was that the network has gone,and didn't came back(i have to
> reboot).:(

onboard pciide controllers are somewhat special, as they're integrated
to the chipset. It's possible they don't use the same data path as
add-on pci cards, and may block the PCI bus or memory access for longer.
Maybe the RealTek chipset doens't handle very well errors resulting from
PCI contention.

> 
> But using a 3com network card instead of RealTek one i got:
> 
> 5000+0 records in
> 5000+0 records out
> 5242880000 bytes transferred in 573 secs (9149877 bytes/sec)
> 5000+0 records in
> 5000+0 records out
> 5242880000 bytes transferred in 573 secs (9149877 bytes/sec)
> 5000+0 records in
> 5000+0 records out
> 5242880000 bytes transferred in 1270 secs (4128251 bytes/sec)
> 5000+0 records in
> 5000+0 records out
> 5242880000 bytes transferred in 1271 secs (4125003 bytes/sec)
> Is it normal?
> 
> In few words ,it's possible make a raid 5 array using on-board IDE
> controllers?

2 IDE disks on the same channel isn't a good idea - it's not SCSI.
I would get a promise or HPT add-on controller (they're cheap now) and
use only one disk per channel. You'll get much better performances.

On my test system I have 5 drives (one on onboard i810, one on HPT366,
one on Promise Ultra66, one on Promise Ultra100 and one on Highpoint HPT370),
and I can get full speed out of each drive at the same time, for a total
of 100MB/s

--
Manuel Bouyer <bouyer@antioche.eu.org>
--