Tier I data centres provide a dedicated site infrastructure to support IT Systems and include:
- A dedicated space for IT systems
- A UPS to filter power spikes, sags and protect against momentary outages
- Dedicated Cooling Equipment
- A Backup Generator to protect against prolonged outages
There is a single power path delivering power to the load and redundancy is not required. As a result any component or distribution path failure will impact the computer systems.
Standby Power Flow Schematic for a Tier I Data Center
During normal operation the UPS is providing clean power and protecting the load. A short term power outage will see the UPS continue to provide power to the computers but the cooling system will be shut down. During extended outages the generators will activate allowing continuing operation of the computers and the cooling system will restart. Any planned work will more than likely require the computer systems to be shut down.
Tier I data Centres have an availability of 99.671%, which equates to over 28.8 hours downtime per year (Planned and Unplanned).
For a typical computer room, a Tier 1 set up is more than likely adequate, with the addition perhaps of a redundant UPS module (see Tier II). The use of a generator is optional and dependent upon the impact of downtime to the business. The IT equipment can be configured to shut down gracefully in the event of a extended power failure, and the fact that lost data has been avoided is probably acceptable for many businesses.
