A review of data-centre Tier Classifications
Tue 21 Jun 2016

Information technology clients expect an availability of 99.999%, ‘Five-Nines’
The substantial investment that a business makes to achieve Five- Nines in its computer hardware and software platforms is unlikely to be sufficient unless matched by a site mechanical & electrical infrastructure that can support their availability goals. Data-centre’s are classified by their Availability which comes down to their capability to achieve concurrent maintenance and fault tolerance but their overall site ‘Tier’ rating is dependent upon all aspects of the site infrastructure and will be the lowest of the individual sub system ratings covering such aspects as power, cooling and connectivity etc. It is important to be aware that operational issues (how the site is operated once constructed) also plays a significant role in what site availability is actually achieved.
All too often it is assumed that installing a UPS is the end of any problems but, if the overall design, installation and ongoing service support is handled badly it could just be the beginning of the problems. For example, it is vital to ensure that the Mean-Time-To- Repair (MTTR) of the system is kept to a minimum if the highest overall availability is to be achieved. Nowhere is this more important than in the design of data-centers.