FYI, Electrical Code (NECA) and most datacenters require the power not to be loaded beyond 80% of breaker capacity... i.e. 16amp draw on a 20amp circuit.
Additionally, one also has to have head room on the power circuit to deal with start up draw (current rush). It's not pretty when you have a crap load of servers starting up all together :) Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: [email protected] > From: "Eric Kuhnke" <[email protected]> > To: [email protected] > Sent: Saturday, May 14, 2016 7:50:22 PM > Subject: Re: [AFMUG] Data center temperatures > How does a 44U cabinet need 208V 60A for storage arrays? > In a 4U chassis the max hard drives (front and rear) is about 60 x 3.5"... > Say each drive is 7.5W TDP, that's 450W of drives. Add another 200W for > controller/motherboard and fans. 650W in 4U. > 44 / 4 = 11 > Multply by 650 > 7150W > More realistically with a normal amount of drives (like 40 per 4U) a single > 208 > 30A is sufficient, > 208 x 30 = 6240W > Run at max 0.85 load on the circuit, so > 6240 x 0.85 = 5304W > In a really dense 2.5" environment all of the above is of course invalid, you > could probably need up to 7900W per cabinet > Then there's 52U cabinets as well... > On May 13, 2016 6:16 PM, "Paul Stewart" < [email protected] > wrote: >> Yup … general trends on new data centers are pushing those temperatures >> higher >> for efficiency but also with better designs .. >> One of our data centers runs at 78F and have no issues – each cabinet is >> standard 208V 30A as you mention but can go per cabinet much higher if needed >> (ie. 208V 60A for storage arrays) >> From: Af [mailto: [email protected] ] On Behalf Of Eric Kuhnke >> Sent: May 11, 2016 5:15 PM >> To: [email protected] >> Subject: Re: [AFMUG] Data center temperatures >> There have been some fairly large data set studies done shown that air intake >> temperature for huge numbers of servers, at 77-78F does not correlate with a >> statistically significant rate of failure. >> http://www.datacenterknowledge.com/archives/2008/09/18/intel-servers-do-fine-with-outside-air/ >> http://www.datacenterknowledge.com/archives/2012/03/23/too-hot-for-humans-but-google-servers-keep-humming/ >> how/what you do for cooling is definitely dependent on the load. Designing a >> colo facility to use a full 208V 30A circuit per cabinet (5.5kW) in a >> hot/cold >> air separated configuration is very different than 'normal' older facilities >> that are one large open room. >> On Wed, May 11, 2016 at 1:58 PM, Ken Hohhof < [email protected] > wrote: >>> I’m not sure you can answer the question without knowing the max heat load >>> per >>> cabinet and how you manage airflow in the cabinets. >>> AFAIK it used to be standard practice to keep data centers as cold as >>> possible >>> without requiring people to wear parkas, but energy efficiency is a >>> consideration now. >>> From: That One Guy /sarcasm >>> Sent: Wednesday, May 11, 2016 3:51 PM >>> To: [email protected] >>> Subject: Re: [AFMUG] Data center temperatures >>> apparently 72 is the the ideal for our noc, i set our thermostat to 60 and >>> it >>> always gets turned back to 72, so i just say fuck it, I wanted new gear in >>> the >>> racks anyway >>> On Wed, May 11, 2016 at 3:46 PM, Larry Smith < [email protected] > wrote: >>>> On Wed May 11 2016 15:37, Josh Luthman wrote: >>>> > Just curious what the ideal temp is for a data center. Our really nice >>>> > building that Sprint ditched ranges from 60 to 90F (on a site monitor). >>>> I try to keep my NOC room at about 62F, that puts many of the CPU's >>>> at 83 to 90F. Many of the bigger places I visit will generally be 55 to >>>> 60F. >>>> Loads of computers (data center type) are primarily groupings of little >>>> heaters... >>>> -- >>>> Larry Smith >>>> [email protected] >>> -- >>> If you only see yourself as part of the team but you don't see your team as >>> part >>> of yourself you have already failed as part of the team.
