Title: Racks
Course: 2016FA-MCO-110-401 > Section: Module 11: Data Centers

Click here for a downloadable version of this document:(EXTERNAL) Racks

Rack Placement, Layout, and Installation

"Computer Rack HP" by Yann, Wikimedia Commons is licensed under CC BY-SA 3.0

The placement of IT equipment racks throughout the data center floor space is key for both installation and operational efficiency. Pre-planned floor layouts significant decrease capital costs by allowing data center management to minimize the length of power and communication cabling as well as establish systems for installing new equipment in a neat and orderly fashion. Additionally, MCO technicians should weigh in on the planning process to make sure cooling is being utilized in the best way possible. For instance, simply installing racks and cabinets because there is enough room in a given footprint creates problems like the intake of one set of servers being adjacent to the hot air exhaust of another set of equipment.

Rack Placement, Layout, and Installation

The placement of IT equipment racks throughout the data center floor space is key for both installation and operational efficiency. Pre-planned floor layouts significant decrease capital costs by allowing data center management to minimize the length of power and communication cabling as well as establish systems for installing new equipment in a neat and orderly fashion. Additionally, MCO technicians should weigh in on the planning process to make sure cooling is being utilized in the best way possible. For instance, simply installing racks and cabinets because there is enough room in a given footprint creates problems like the intake of one set of servers being adjacent to the hot air exhaust of another set of equipment.

Rack Power Distribution

The distribution of power to, and between racks on the data center floor is almost as much of an art as it is a science. Design requirements will dictate how much power needs to be delivered, to what systems, and the levels of redundancy & reliability necessary for business continuity. A few considerations are:

- Dedicated circuits – both for sections of the floor, or individual cabinets
- Circuit sizing – dictated by design, but a good rule of thumb is the maximum expected load should be < 80% of the circuit size. (For instance, a 20A circuit should not have more than 16A of load installed)
- Rack flexibility is important for enterprise data centers that have all sorts of IT setups installed – the ability to install different sized gear with varied power and networking requirements
- Growth potential is very hard to determine in the rapid evolving IT/data industry, but all efforts should be made to provide design allowances for growth in scale, connectivity, and power density. It is extremely expensive and invasive to attempt to retrofit a live data center with new infrastructure requirements.

Rack Cooling

No two data centers are alike, and not all of them are pre-planned and well laid out – some just grow organically – which may require the use of rack-level cooling. A few examples of this application are:

- Above Floor – cool air may be ducted specifically from overhead towards a single rack or section of cabinets.
- Below floor – cooling air may be ducted up into a cabinet from below, or towards standalone perforated tiles.
- Spot Coolers – more recent innovations in a variety of designs, usually with small lines of refrigerant or chilled water piped directly to heat exchangers with fans installed at the top, bottom, or sides of individual racks.

Objectives met:
- C11
- 11.12