DATA CENTERS, PART 2

The general attributes of each Data Center Tier are presented below.


This Part-2. Click here to read Part-1. Click here to read Part-3. A new tab or window will open for each post.

Data Centers are classified into four tiers. Tier-1 refers to a basic facility and Tier-4, to the most reliable and sophisticated type. This post goes into further detail about each tier.

Tier-4

1. takes 15 to 20 months to plan and implement
2. is the most expensive type and most costly to operate
3. is housed in a stand-alone building
4. is staffed "24 x 7 x forever"
5. intentionally uses only 90% or less of its total load capacity.
6. has at least two active distribution paths for connectivity, power, and cooling
7. All paths are physically separated and always active. The failure of any single active path will not impact uptime.
8. All components are physically separated. The failure of any single subsystem will not impact uptime. All IT equipment is dual-powered and installed so as to be compatible with the site's topology. Any non-compliant end-user equipment is equipped with point-of-use switches.
9. Preventive maintenance can be safely done without disrupting operations. Maintenance on any and every system or component can be performed using backup components and distribution paths. The failure of key nexus points will not impact uptime.
10. A Tier-4 site has a fault-tolerant infrastructure. The site location is not susceptible to any single major disruption. This extends the capability of the lower tier through the addition of measures that will prevent disruption even when crucial components unexpectedly fail. Tier-3 only allows the preventive maintenance of crucial components and has no safety provision for the unexpected failure of crucial components.
11. All IT equipment is dual-powered and installed so as to be compatible with the site's topology. Any non-compliant end-user equipment is equipped with point-of-use switches. Dual-power technology requires two completely independent systems that feed power via two paths. Research has determined that 98% of all failures occur between the UPS and the computer load.

Tier-3

1. is housed in a stand-alone building
2. takes 15 to 20 months to plan and implement
3. is typically staffed for two shifts or more intentionally
4. uses only 90% or less of its total load capacity
5. has at least two paths for connectivity, power, and cooling distribution.
6. All paths are physically separated. However, only one path is active at any time. The unexpected failure of an active path will impact uptime.
7. All components are physically separated. The failure of any single subsystem will not impact uptime. All IT equipment is dual-powered and installed so as to be compatible with the site's topology. Any non-compliant end-user equipment is equipped with point-of-use switches.
8. Preventive maintenance can be safely done without disrupting operations. Maintenance on any and every subsystem or component can be performed using backup components and distribution paths.
9. This has a concurrently maintainable infrastructure. The site location is not susceptible to unexpected minor disruptions. This extends the capability of the lower tier through the creation of a second distribution path for connectivity, power, and cooling.

Tier-2

1. may be housed in a wing or floor of an existing building
2. takes three to six months to plan and implement
3. is typically staffed for one shift
4. has only one path for power and cooling; may have a second path for connectivity
5. has a backup set of only critical power and cooling components, e.g., extra UPS batteries, cooling units, chillers, pumps, and engine generators
6. The unexpected failure of any component or path will impact uptime.
7. Operational errors will likely cause a disruption.
8. The site location is susceptible to all kinds of disruptions. The infrastructure must be shut down to safely perform preventive maintenance.

Tier-1

1. may be housed in a room or wing of an existing building
2. typically takes less than three months to plan and implement
3. is not staffed
4. has only one path for connectivity, power, and cooling
5. The unexpected failure of any component or path will impact uptime.
6. Operational errors will cause a disruption.
7. The site location is susceptible to all kinds of disruptions. The facility must be shut down to safely perform preventive maintenance.

Despite its basic infrastructure, a Tier-1 center still provides a better IT environment because:

1. It offers dedicated space.
2. Its online UPS system does a better job than a standby UPS at filtering power spikes, compensating for sags, and covering momentary outages.
3. It has nonstop, dedicated cooling equipment.
4. It has an engine generator to withstand extended power outages.