[Info-vax] Pile of RX2660s

[JF Mezei]

On 13-12-30 18:18, Jan-Erik Soderholm wrote:

> Why would they put the second fan in if it didn't made a
> significant/needed difference (worth the extra fan)?

Because HP got a "buy one get one free" special from the fan company ?
:-) :-)

Note that my Xserve (1 1U server) has such fans in series, but they are
tiny fans.

> http://www.macpartsonline.com/076-1339-fan-array-with-foam-xserve-early-2009-a1279.html

And yes, they are noisy, especially when they speed up when I do a video
rendering that makes full use of the CPU.


But on a 2U server like the RX2xxx series, I have to wonder how
necessary it is to have doubled fans, especially if under normal
circumstances, the fans do not operate at full speed. The bigger fans
can really push much more air through since the motor now represents a
much small fraction of the diametre of the fan,

Note that if the second fan has different blades and was able to operate
at different speed for same CFM values, it would really drop the noise
levels substantially.