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