ServerHouse - Colocation Glossary

1. Server Size

Our data centres have racks designed to take high density 19" rack mounted computer systems. We sell space by the "U" A whole rack is 47U, A half rack 22U and a quarter rack 11U All server manufactures manufacture servers specifically designed for racks; these are very deep, 19" wide and not very high, typically under 44mm for a dual core system with up to 3 hard disks. We can accommodate any size of hardware, be it floor mounted a laptop or desktop case, but be wary of the air flow, often a 2U case offer more flexibility and uses less power than a 1U equivalent. 1U = 1 Rack Unit - 44.55mm high, 900mm deep and 482.6mm wide

2. AirFlow

You must ensure your hardware has sufficient air flow to work in a data centre environment, rack mount servers are designed to push the air not only out of their own case, but also out of the rack itself. A desktop PC with normal fans is designed to be quiet, in a DC sound levels are of minimal concern. We recommend high speed temperature controlled fans and rack mountable hardware.

3. UPS

Uninterruptible Power Supply . Provides power to a mission critical load in the event of a mains power failure. The UPS itself is either powered by a fuel cell, battery or rotary energy store. Fuel Cell's are expensive, batteries heavy and large and rotary energy stores typically only allow for a 7 second outage. DateCentre UPS's also filter the power supply to the load.
ServerHouse use batteries as they're scalable, reliable and offer a long protection period

Run Time and Autonomy

Used to describe how long a UPS or Generator can run without interruption

Generator

Engine with a large alternator attached to generate electrical current, in our case used to power the entire building (lift, lights, computers, cooling, kettle and heating) in the event of a power outage >20 seconds)

PUE

Power Usage efficiency, a ratio indicating a data centre.s efficiency by calculating the amount of power required to service the load. A PUE of 2 would be 1kW of computing load and 1kW of cooling/lighting. The lower the PUE the more efficient the facility. Design PUE and operational PUE can often vary, ServerHouse has an average PUE of 1.32

Close Control

Air conditioning system which controls both the temperature and humidity. Normal air conditioning systems only control the temperature, they normally achieve some level of cooling by reducing the humidity in the air, this can create a highly static environment. Static is a risk to servers. ServerHouse has close control air conditioning which ensures the humidity is well within safe levels.

Floor Loading

The maximum mass the floor can support, normally measured in kN per SqM (kilo newtons per square meter)

FM200

An inert gas which once released is able to extinguish a fire by both cooling and destabilizing the chemical reaction of the fire. It's safe to breath and means data centre operations can run continuously, even in the event of a fire

VESDA

Very Early Smoke Detection Apparatus(VESDA). Most spoke detectors rely on smoke to rise to them in order to detect a fire. This means a fire could be taking hold while smoke is rising. VESDA sucks air across a detector to reduce the time it takes to detect smoke.

Access Control

Access control systems both control access (much like a key would) but also record access so if you try a door you're not allowed through it will be recorded. If you go through a door it will be recorded. If you steal a key from site it can be disabled.

Biometric

Security is managed by a biometric system, i.e your finger print, palm scan, iris etc are recorded and used to prove your identity

N+1

Where N is the requirement (what the data centre needs) +1 is the spare capacity. This may be in the form of an oversized unit or a hot or cold spare. But be careful, an oversized unit doesn't always provide redundancy, only extra capacity. Ensure you ask any data centre to explain their N+1.

N+N

Where N is the requirement, +N is a seperate and equally sized backup system. For example Two generators each able to support the full load.

S+S

Two totally independent systems. Far superior to N+N. N+N can existwith multiple single points of failure (i.e two UPS's but both feed from the same supply), S+S indicates there are none

Single point of Failure

A component in any system which if it should fail will break the entire system. No single point of failure means any component can break without affecting the overall systems performance.

Hot Aisle

The aisle between two rows of racks that is intentionally hot because the servers in adjacent racks are feeding warm air into it.

Cold Aisle

The aisle between two rows of racks that is intentionally cold and supplies cold air to the servers in adjacent rows.

Hot of Cold Aisle Containment

Hot or Cold Aisle Containment Building a sealed environment around the Hot or Cold Aisle to improve cooling efficiency by forcing as much air as possible through servers before returning to the air conditioning unit.

Carrier Neutral

Many colocation providers also own the data centre and limit your connectivity to their own offering. ServerHouse is carrier neutral and we don't restrict or limit with who or how you get your connectivity. This means you can have diversity, better pricing and change providers without moving your servers

Shared Racks

A Shared Rack is a 47U rack which is used by multiple companies, typically this is done to save money, by sharing space it saves your provider money. However there are two problems with this. The first is the power supply, should another person in that rack overload the breaker to the rack all the customers in that rack will lose power. The second is idle hands, when other occupants slide their servers in and out or reach into the rack there is a chance they can unintentionally disconnect your server. For these reasons ServerHouse don't provide shared rack space, we do however provide 11U rack cells so you can have the cost saving without compromising on security or reliability

Service Contention

When your service is shared, this means you may be sharing your bandwidth with between 10 and 50 other clients. We don't believe in service contention so for every Mb of IP we sell we ensure there is capacity in our network to support it. In addition to this we monitor our bandwidth usage in 1 minute intervals to ensure every link have at no more than 20% utilization.

Dedicated servers

A dedicated server is a item of hardware supplied by server hosting companies to simplify the colocation process, typically the server hosting company would purchase the server on the clients behalf and maintain it's hardware for the duration of the contract. ServerHouse don't offer this service because it's expensive for the client, while set-up costs are lower, after 8-10 months it's more expensive, after 2-3 years the client ends up paying a huge premium for a very out dated hardware. We find customers get find better value and service by providing the hardware themselves

Sales: 01329 800 911