Yosef makes some really good points, which I will attempt to itemize.

* You are not enhancing the SCSI speeds by attaching the SCSI HBA to fiber.

This very true, a classic HP3000 has an NIO bus rated at 32MB per second, fiber
can be overkill.

*  it is a support/maintenance nightmare.

Again, that CAN be true.  Not only is HP's supported solution of the A5814A a
support nightmare.  It requires up to 8 A5814A fiber/SCSI routers (list price
$7200) and one brocade switch ($3000?).  So not only is it a maintenance
nightmare but it is a budget blackhole as well.

* What is the benefit of a solution?

This I can answer from experience.  HP's offical supported solution is a
support nightmare.  But there are other solutions that offer low cost, simple
fiber/SCSI connectivity.

/plug

The benefit is that the classic HP3000's can now access high-speed, high
availability, fault tolerate disc subsystems at a fraction of the cost.

For example, it is possible to buy a VA7100 for 20K.  Paying 55 to 60K just for
the "cable" that goes between them is a bit excessive.

I use an SA-40 from Crossroads, it has up to 4 fiber connections and up to 8
SCSI connections.  Setup is simple and easy.  Since it is a router, it does not
require a fiber switch.  Cost is approx 15K.

/end-plug

* does anyone have any real world performance

Yes, most high speed fiber arrays are more powerful than any classic 3000
backplane.  For that reason, I wouldn't recommend more than 8 SCSI paths, and
on lower end 3000's, even less paths are required.

From experience I have learned, for the 3000, always use smaller size luns and
more of them.  For example

A VA7100 has 15 * 36GB drives, given the autoraid part this will come to about
410GB so lets say 400GB for ease of math.

There are 8 SCSI Channels to the 3000.

There are a 1000 ways to configure the VA7100, starting with 8 50GB luns, 1 per
channel.  I DON'T recommend this configuration.

A better solution is to configure 8 * 6GB lun's per channel.  This will improve
concurrency and I/O.

Better yet is to split the 400GB across multiple volume sets and multiple
transaction managers... but that depends on the I/O.  I digress.

The bottom line is that a good fiber/scsi router can provide access to the nice
new disk solution that managment is so proud of.  It is not necessary to
further isolate the 3000 in the corner of the computer room.

HTH,

-Craig Lalley
EchoTech, Inc.





--- Yosef Rosenblatt <[log in to unmask]> wrote:
> One must keep in mind that one's data transfer rate is only a fast as the
> slowest device one has attached to one's SAN. This is why we speak of
> bottlenecks and not bottlebottoms. You are not enhancing the SCSI speeds by
> attaching the SCSI HBA to fibre.
>
> My former employer, EMC, did not support the Fibre Bridge solution on any
> platform. The reason was that they saw little performance enhancement and a
> great deal of trouble in getting all the elements to work. This is to say
> nothing of the finger-pointing between server, disk, switch and bridge
> support groups, i.e. it is a support/maintenance nightmare. (I obviously do
> not speak for EMC.)
>
> What is the benefit of the Fibre Bridge solution? Does anybody have real
> performance data that they are willing to share with Mr. Anderson? It would
> be a shame for him to go through with this kludge without at least knowing
> what benefit there may be.
>
> On the other hand I may be completely wrong.
>
> Pray for Peace,
> Yosef
>
> * To join/leave the list, search archives, change list settings, *
> * etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
>




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