Four Types of Tier Classification Of Email Hosting Infrastructure

May 28, 2011 by  Filed under: Web Hosting 

You may have seen the description of features and services of email hosting companies. While poring over each service or feature, you may have noticed a few mentions of a first-class infrastructure or a Tier-1 classification for data centers. These data centers are where the email accounts of clients are stored and the rating of Tier-1 means something more than good service. To help you understand the kind of service these email hosts provide, you must learn first what the Tier Classifications are and their role in setting standards of quality in data management.

The four-tier classification serves as a benchmarking system for clients to gauge the level of performance a company provides. Based on the classification topology drawn up by the Uptime Institute Organization, the following tiers are explained as follows:

Tier-1 Basic Data Center

Most companies that provide email hosting and web hosting services use Tier-1 facilities, which provide basic features, such as cooling and power, with no capacity for backup. This is the reason why most websites or email providers would have scheduled downtimes for maintenance. They last about half an hour to two hours, depending on whether it is just a regular maintenance or it is an emergency repair.

Typically, Tier-1 websites experience at most two shutdowns each year for repair work. On average, there is a 1.2 chance of needing component replacements or experiencing equipment failures. These averages could cost a company about 28.8 hours of downtime each year, or 99.67% availability.

Tier-2 Redundant Data Center

Tier-2 facilities provide redundant capacity, which allows technicians to replace or repair components without causing shutdowns. This reduces the incidence of unplanned outages to just one each year. Server maintenance can be scheduled three times over a two-year period. However, there is little difference in availability between Tier-1 and Tier-2, which promises 99.75% availability per year.

Tier-3 Redundant Data Center With Concurrent Maintenance

Similar to a Tier-2 infrastructure, a Tier-3 facility has redundant components, but with a big difference in quality of maintenance. Tier-3 servers can support maintenance periods without any effect on data processing. Clients will not even know the data centers are undergoing maintenance. Because of this capacity for concurrent maintenance, sites do not experience annual shutdowns. Any unplanned outages total only 1.6 hours each year, thus delivering about 99.98% availability to site visitors.

Tier-4 Fault-Tolerant Data Center

Clients that use Tier-4 data centers do not experience downtimes for whatever reason. A Tier-4 facility have multiple, independent and physically separate systems. These qualities lead to more diverse and active data processing paths. Losing one path will not affect the others, which leads to high tolerance to facility-related failures. Any unplanned outages are reduced to less than an hour each year, which yields to 99.99% availability.

As a general note to tier-type ratings, any rating that does not reach the standard for each Tier will not bring the facility to that Tier level. Even when the difference is less than a point, the fractional rating is not acceptable. The sources for the statistics and proportions of four-tier descriptions for email hosting facilities come from the Telecommunications Industry Association (TIA) specification TIA-942 and from The Uptime Institute.

Jerlou Thompson is a professional end-user technology consultant for companies that opt for email hosting as a business solution. Visit Jerlou Thompson’s site where he reveals how hosted emails can boost your business to the top. Select the right email hosting packages that suit your company’s needs.

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