[rescue] Sun Systems need to go away

[Peter Stokes]

On 27 Feb 2014, at 10:42, microcode at zoho.com wrote:

> On Thu, Feb 27, 2014 at 10:14:27AM +0000, Peter Stokes wrote:
>>> On the Sun Fires, the second PSU is required for cooling even when it is
>> not
>>> supplying power. The doc says you should not run with only one of two
PSUs
>>> installed. So you're spinning extra fans and pushing air and heating up
>> your
>>> box for nothing, until you actually need the second PSU.
>>
>> Not strictly true, there was a blanking module which was shipped in place
of
>> one of the PSUs on some of the low spec versions of the V240. In general
they
>> will work fine with just one attached as they were designed as redundant.
>
> Well, the V440 doc clearly states in more than one place the machine should
> not be run with only one of the two PSUs, but checking now I don't find
> similar verbiage in the V210/240 doc. There is a difference in the manual
> sets I have and I see a diagnostics and troubleshooting guide for the V440
> but I don't have a similar manual for the V240.
>
> Perhaps I was wrong, if so, I'm sorry for the misstatement. Still, based on
> the info in the V440 doc and the fact these boxes do throw a lot of heat, I
> would not want to run a dual PSU model with only one PSU.
>
Hi

Not having a go, just mentioning about it, if only for reliability it makes
much more sense to run with dual PSU on V240, and there should not be a
significant extra cost to run as the power taken is the same, just the extra
fan and some losses in the 2nd PSU, which should not be much.

As to heat, on the V240, the main board heat has no bearing on the PSU fans
etc, it is all via the motherboard and CPU fans which vent out the back, not
via the PSU, so for lightly loaded system, single PSU should be fine.

On the V440, you would never normally see single PSU and for sure it does
complain if one is not present, but have a niggling in the back of my mind
that there was a single PSU version sold originally, but far too long ago to
remember correctly and I have not seen a single PSU version, again why bother.
One point to mention is that whilst the V240 PSUs are pretty bullet proof and
very very rarely fail, the original fans in the V440 PSU (early 501-1501 p/n
ones) had fans with poor bearings and they always failed/ran slow causing the
PSU to shutdown. It is possible to replace the bearings with decent ones as
finding a replacement fan was pretty impossible as OEM version I think. Later
PSUs had much better fans which rarely failed. If you come across failed V440
PSUs, then always check the fan as on early PSUs it accounted for 95% of
failures in my experience.

Peter