| Selecting a Colocation Facility | | | | * Performance-based routing, which continuously |
| Communications and data access are integral for | | | | adjusts routes to find the most effective one, rather |
| business operations. Websites, email and messaging | | | | than the least expensive |
| services, and servers have to be up and protected | | | | * Routing among more than three, and preferably |
| for business communications to function. Data | | | | four or five, Internet backbones |
| centers that house mission-critical infrastructure - the | | | | A hardware-redundant, dynamically adjusting routing |
| most vital parts of the company network, like | | | | system creates a self-healing network that offsets |
| servers and databases - must sustain the power, | | | | backbone problems, traffic and load, and hardware |
| climate-control and connectivity that network | | | | failures so that service doesn't suffer. |
| infrastructure demands. | | | | Climate Control |
| Redundancy | | | | The design of the facility itself has an impact on the |
| The colocation facility should have redundant | | | | performance of systems housed in the colocation |
| systems, with sufficient capacity, at every point of | | | | center. Server rooms should control air flow between |
| operation, from climate control systems to network | | | | rows. The heat generated by servers is blown in one |
| equipment. Having multiple units for to handle capacity | | | | row, and cool air can be drawn in from another row. |
| is not the same as redundancy. All systems should be | | | | Designated hot and cold rows circulate the air to |
| in an n+1 configuration; for example, if there are two | | | | keep servers from overheating. |
| units, they should both run at less than 50% capacity | | | | Appropriately-sized and redundant climate-control |
| so that if one fails, the other can still handle the load; | | | | units create cold air and control humidity. Servers |
| if there are three units, then they should be at 66% | | | | have strict climate requirements, about 72 degrees |
| capacity. | | | | and 45% humidity. Colos must have both chillers for |
| Superior Connectivity | | | | the facility climate control and computer room air |
| Several factors determine the quality of a colocation | | | | conditioning (CRAC) units for the server rooms. The |
| center's Internet connectivity: | | | | capacity for cooling units is calculated by dividing the |
| * The number of Internet backbones | | | | total tonnage by the square footage. For example, if |
| * Total available bandwidth | | | | there are two 50-ton chillers and a 4000 square foot |
| * Latency, packet loss, and jitter | | | | facility, the chiller capacity is 0.040 tons/foot. Chillers |
| * Uptime | | | | and CRAC units should each have a capacity of 0.30 |
| Colocation data centers provide Internet access to | | | | tons/foot or higher. |
| tier-1 carriers, tier-2 carriers, or carrier-neutral access. | | | | Power |
| Tier-1 services provide direct access to one of the | | | | If there is a failure of the primary power source, the |
| major Internet backbone networks, like AT&T. | | | | generators and UPS are vital to keep the network |
| Tier-2 providers routes traffic among multiple tier-1 | | | | online. The UPSs run the servers while power |
| providers, and reliability and speed are influenced by | | | | switches from regular electricity to generators, and |
| how effectively traffic is routed. Carrier-neutral | | | | there must be generators onsite for immediate |
| access allows service from any carrier, but requires | | | | backup power. The power system should have the |
| that customers configure their own routing and | | | | following features: |
| maintain their own connections to Internet | | | | * Failover practices for switching to redundant |
| backbones. Tier-2 access is preferable because | | | | generator and UPS systems |
| routing is configured by the colocation facility and it's | | | | * Multiple, redundant UPS, systems, since UPSs fail |
| more reliable because more backbones are available, | | | | routinely |
| which increases uptime and network performance. | | | | * A generator large enough to handle 1.5 times the |
| Load-Responsive Routing | | | | normal building load |
| The way that Internet traffic is routed, both the | | | | Making a Decision |
| hardware and routing logic, has a significant effect on | | | | Keeping servers offsite can be a good decision |
| connectivity. Effective routing covers three areas: | | | | logistically, but only if the data center provides a |
| * Redundant routers and switches with full capacity | | | | reliable, secure network environment. |
| for all customers | | | | |