[Sunhelp] Problem with E220 "redundant" power supplies

[Bill Bradford]

On Wed, Jun 21, 2000 at 08:57:45PM -0500, Tony Alberti wrote:
> How many disks were in the 220?

Two, the maximum.  18gig drives.

> I have had a similar situation on an E250.
> I asked one of the Sun FE's here in Chicago
> to explain this.  I was told that the dual power
> supplies in a 250 aren't truely redundant when
> the machine is loaded. If you have two power
> supplies and only 1 internal disk, there is enough
> power in one power supply to handle the load,
> so the redundancy works.   However when you
> have all 6 HDs in a 250, that second power supply
> uses about 75% of its output to drive the disk
> backplane.   It is no longer redundant.
> If the machine had truely redundant power
> supplies, one could handle the load of the
> system AND all 6 disks, so all you would
> need for operation was 1, and the second
> for redundancy.   Try to order an E250
> from Sun configured for 6 internal disks
> and 1 powersupply.  They will NOT
> sell you that configuration.  If you
> want 2 internal disks and 1 power supply,
> they will sell that to you (assuming the mainboard
> had the same loaded config of 2 400mHz CPUS and
> 2 gig memory in both configurations).
> I suspect something similar probably occured in your 220.
> Although there are less internal disks in a 220, perhaps the
> power supplies are less as well.
> Tony

Thanks for the note, helps explain that I'm *not* going crazy.

Bill

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