In my previous blog i wrote about
Microsoft Azure data center. It was a huge data center in terms of size, money
and all other aspects. The topic for this blog came from professor William
Slater's lecture 2 notes. There are many aspects one has to keep in mind while constructing a data center and one of them is cooling the servers or to
maintain appropriate temperature so that servers can run efficiently. Two
employee of Microsoft Christian Belady, principal power and cooling architect
and Sean James, facility program manager went out of the box and showed that
little water, uncontrolled temperature and even leaves sucked inside server fan
may have no effects on server.
They setup a tent outside and ran 5
previously used but spare HP DL585 servers in the tent. There were few
incidents that had unexpected outcomes.
- Water came inside the tent and fall into racks but
server continued to run.
- Windstorm blew a section of the tent but still server
continued to run.
- A leaf was sucked onto server fascia and the servers
still continued to run.
This approach has much lower PUE
around 1.0(Power usage effectiveness) than compared to other data centers.
After this experiment the question rises is this approach should be implemented
in order to reduce cost related in constructing a data center. From the above
outcomes the servers are quite rough and tough as they sustained water and
wind. As the PUE was around 1.0 so data center should use outside air to cool
the data center through economization process. Since cold environment will not
be available throughout the year so the temperature range of servers should be
enough so as need to provide mechanical cooling is minimum. Also according to
Christian offline UPS technologies should
be used. Most UPS are online, in that they rectify alternating current (AC) to
battery-level direct current (DC) and then invert the battery-level DC to 120
or 240 volts AC) Although this process provides better power smoothing, the
double conversion is inefficient. Offline UPSs eliminate this double
conversion, thus providing greater UPS efficiency.
But before implementing
this type of approach more experiment should be performed in order for more
accurate outcomes. Intel Corp. conducted a test in which data
center relied exclusively on outside air for cooling and installed no humidity
controller and minimal air filters. They found that test environment had very
similar failure as a traditional data center has and the changes could save
$2.87 million annually for 10 MW data centers. Therefore such type of tests
should be conducted frequently to come in a concrete conclusion.
