[Sunhelp] Problem with E220 "redundant" power supplies

[James Lockwood]

On Wed, 21 Jun 2000, Tony Alberti wrote:

> 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

This is wrong.  Dual powersupplies in a 450 are not redundant in a maximal
configuration, but they are sufficient for a 250.

> 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

This is incorrect.  I have 4 E250's with 6x18GB, 1GB RAM and dual 400MHz
CPU's.  All were ordered in this configuration and came from Sun with one
powersupply, with which they work fine.  The E250 is fully redundant with
two powersupplies in all configurations.  Consult the h/w answerbook for
power capacity planning information.

koffing:/usr/platform/sun4u/sbin% ./prtdiag -v
System Configuration:  Sun Microsystems  sun4u Sun (TM) Enterprise 250 (2
X UltraSPARC-II 400MHz)
System clock frequency: 100 MHz
Memory size: 1024 Megabytes

========================= CPUs =========================

                    Run   Ecache   CPU    CPU
Brd  CPU   Module   MHz     MB    Impl.   Mask
---  ---  -------  -----  ------  ------  ----
SYS     0     0      400     2.0   US-II    10.0
SYS     1     1      400     2.0   US-II    10.0

...

Disk LED Status:        OK = GREEN      ERROR = YELLOW
                DISK  5:    [OK]        DISK  3:    [OK]        DISK  1:
[OK]
                DISK  4:    [OK]        DISK  2:    [OK]        DISK  0:
[OK]

...

Power Supplies:
---------------

Supply     Status
------     ------
  0          OK  

> 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.

The 220 routes power from the sockets on the back differently.  Check the
E220 h/w answerbooks for details.

-James