Tier performance standards

The Uptime Institute tier performance standard system

Tier I is appropriate for firms such as:

Small businesses where information technology primarily enhances internal business process; Companies whose principal use of a “web presence” is as a passive marketing tool; and Internet-based startup companies without quality of service commitments. ...read more

Tier II is appropriate for firms such as:

Small businesses whose IT requirements are mostly limited to traditional normal business hours, allowing system shutdown during “off-hours”; Commercial R&D firms, such as software, who do not typically have “online” or “real-time” service delivery obligations; and Internet-based companies without serious financial penalties for quality of service commitments. ...read more

Tier III is appropriate for firms such as:

Companies that support internal and external clients 24/7 such as service centres and help desks, but can schedule short periods when limited service is acceptable;
Businesses whose information technology resources support automated business processes, so client impacts of system shutdowns are manageable; and Companies spanning multiple time zones with clients and employees spanning regional areas. ...read more
 

Tier IV is appropriate for firms such as:

Companies with an international market presence delivering 24x365 services in a highly competitive client-facing market space; Businesses based on e-commerce, market transactions, or financial settlement processes; and Large, global companies spanning multiple time zones where client access to applications and employee exploitation of information technology is a competitive advantage. ...read more

Information technology customers expect availability of “five nines” or 99.999%. Unfortunately, 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 with a complementary site infrastructure that can support their availability goals. The overall site tier rating is dependant on all aspects of the site infrastructure and will be the lowest of the individual sub system ratings covering such aspects as power, cooling and distribution etc. It is important to be aware that sustainability (how the site is operated once constructed) also plays a significant role in what site availability is actually achieved. All too often people wrongly assume that installing a UPS is the end of their problems. However, if the overall design, installation and ongoing service support is handled badly, it could just be the beginning. For example, it is vital to ensure that the mean time to repair (MTTR) the system is kept to a minimum if the highest overall availability is to be achieved. Nowhere is this more important than with the design of data centres.

Each industry has a unique uptime need driving the site infrastructure tier level required. After careful alignment of IT availability objectives with site infrastructure performance expectations, an informed company may select a site infrastructure based on any of the tier classifications. Data centre owners have the responsibility to determine what tier of functionality is appropriate or required for their sites. As such, it is a business decision to determine the tier classification necessary to support site availability objectives. Part of this decision is to balance the IT operational practices with the facility practices that support the IT world. Once selected, however, the desired tier should be uniformly implemented.