Date: Wed, 5 Apr 1995 00:28:43 +0800 (CST) From: Brian Tao <taob@gate.sinica.edu.tw> Cc: freebsd-current@FreeBSD.org Subject: Re: New installation notes Message-ID: <Pine.BSI.3.91.950405002059.194G-100000@aries.ibms.sinica.edu.tw> In-Reply-To: <199504030803.BAA03823@gndrsh.aac.dev.com>
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On Mon, 3 Apr 1995, Rodney W. Grimes wrote:
>
> > But I were to do
> > something like two 'dd if=blah of=/dev/null bs=65536' on files from
> > each drive simultaneously, I should still be able to hit close to the
> > maximum throughput, no?
>
> Depends on what maximum throughput you are trying to hit.
The disk-to-bus throughput per disk. If the drives are only
capable of about 2 megabytes per second, then assuming the aic7xxx
driver and the AHA-2940 can handle far in excess of that, I should be
able to push close to 4 megabytes per second through the bus?
> I have done dual drive concurrent iozones using 3MB/sec drives and
> saw a very small difference in the numbers for each drive compared
> to running them seperately (ie, the bottleneck was really the drives
> and not the SCSI bus, controller or PCI bus.)
Right, this is what I want to determine. The bottleneck won't be
the Pentium CPU, the PCI bus or the SCSI controller. I figure it's
the disk, but I want to make sure it isn't the driver.
--
Brian ("Though this be madness, yet there is method in't") Tao
taob@gate.sinica.edu.tw <-- work ........ play --> taob@io.org
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