Simpkins, Terry wrote:
> If we "split the bus" on the array mechanism into two separate groups of drives, and
> then connect a separate controller to the other half of the bus.  You can't have the
> hardware mirrored drive on the other controller, (I'm told you can do this on UX).
> It must be on the same path as the "master" drive because MPE sees them as a single
> device.

That isn't exactly accurate. Actually ALL of the drives are accessible
from EITHER controller but of course via different addresses. Your
installer should set the DEFAULT ownership of drives to each controller.
To improve throughput each controller should share the load. Only one
controller is necessary to address ALL of the drives.......but....where
MPE falls short is not having a mechanism for auto fallover of a failing
controller. In other words sysgen reconfiguration would be necessary to
run on a single controller after SP failure in a dual SP configuration.
You could have alternate configurations stored on your system to cover
both cases of a single failing controller but the best solution is to
get it fixed when it breaks. The best news is that SP failures are not
very common.

                          Bob J. -- Ideal Computer Services
                          http://www.icsgroup.net

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