FWIW, from the Maxtor specs, I can expect 9 drives to draw 8.5 amps on the
5v line and 6 amps on the 12v line.
Yes/no/maybe
Primary issue with supporting so many drives is spin-up current,
which could be up to 2.25A 12V per drive. If your controller
delays spinup of some, it will certainly help. This is also an
area where the power supplies you're looking at may help, since
they (should) have a 2nd, semi-isolated 12V rail for CPU (often
listed as two 12V rails (CPU & I/O) on label) , so drive spin-up
current is not as much of an impact on CPU power rail. In this
regard a (properly designed) EPS unit is superior to traditional
ATX PSU of same rated amperage.
With any EPS unit in the wattage range you seek, 9 drives should
not be a problem. You might tally up current usage on 3V/5V
rails though, as often EPS units have lower 5V amps.
"Quiet" operation is not to be expected though, with any PS2 size
outputting that much power it should have fairly high airflow
rate, and preferribly one or more pusher fans on chassis intake
or behind drive bays (depends on server chassis type) such that
PSU fans are moving pre-pressurized air, not doing the work of
drawing air in though passive chassis intake. Of course ambient
air temp can be significant, a 10C temp difference could be
sufficient enough to offset somewhat lower airflow volume.
The extent the airflow volume impacts you can also depend on PSU
chosen. For example the Enermax line has MTBF rating based on
only 70% of rated output, at 25C. Enermax gained their
popularity back in the Pentium 3 era, when average system needed
less power, but as systems continue to use more and more power
the true limitations of an Enermax become more apparent.
