Re: IDE vs SCSI for RAID

[Tobias Diedrich <ranma@example.com>]

Stephen J. Turnbull wrote:

> A P120 + PCI + IDE + 32MB combo didn't give better performance

You did enable Busmaster DMA transfers using hdparm -d1, did you ?
I get 3MB/sec using the default hd settings (16bit I/0, unmaskirq=off,
dma=off, if the kernel does not use dma by default, which seems to be
enabled in newer 2.4 kernels).
6MB/sec with unmaskirq and 32bit I/0.
20MB/sec with unmaskirq and busmaster dma.
(On a Maxtor 40GB 5400 rpm disk)

In contrast to that I get only 20MB/sec on our RAID5 SCSI we use for
one of our Servers at my university (Combined space is 229GB, IBM IDE disks,
rpm unknown, external Tower with integrated controller, attached to
the server using an adaptec AIC7XXX scsi controller).
I suspect that either the raid controller or the scsi interface card
is the bottleneck here...

-- 
Tobias							     PGP-Key: 0x9AC7E0BC