Re: New 270.

[Matthias Oertli <matthias.oertli@xxxxxxxxxx>]

Andy,

Thank you very much for your reply. It's the explanation I needed!
I will stick with the #2763.
Best regards,
Matthias

>
> I went back to some of your earlier posts.  You are replacing a 9402-400
> (2131) with a 9406-270 (2431).  Your current system has six drives,
> mirrored load source with a RAID set of four.  You are moving from a 20
> CPW machine to a 465/30 CPW machine.  This new machine will fly on your
> current workload.  Your users will be very impressed.  You've stated
> that you have 20-30 users, I assume that this is total workstations, not
> the number of people who are likely to hit the enter key on a
> transaction at the same time.  Even with some normal batch throughput,
> this is a very small workload, probably considerably smaller than the
> interactive workload described in the Disk Arm Requirements document.
>
> I agree with your hardware and software vendors.  Unless you are
> planning on adding new workloads, either disk controller would probably
> give you comparable performance.  Two of the significant differentiators
> between the two are the size of write cache and the number of disks
> which can be attached.  In your situation, it probably doesn't matter to
> you whether you can attach 12 (#2763) or 18 (#4778) disk units.  The
> #2763 has a write cache of 10 MB versus the 104 MB of the #4778.  It
> probably doesn't matter to you whether you can compress your disk
> storage or not, or whether you can attach an adaptive cache device.
>
> The only significant variable between the controllers in your
> configuration would be the size of the write cache.  If you think of how
> many adds/updates are occurring on your system at any one time, do you
> think you will exceed 10 MB?  It doesn't sound like it to me.
>
> It sounds like money is an important factor in this purchase; I would go
> with the lesser of the two controllers.  I don't think there would be a
> noticeable difference between the two.
>
> Regards,
> Andy Nolen-Parkhouse
>

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Matthias Oertli   matthias.oertli@mdi.com.au