Why you’re better off with a TIER 3 datacenter

Businesses are becoming increasingly dependent on IT. With this, the availability of IT systems it becoming crucial for business continuity. Unavailable systems don’t just cause financial damage, but can also damage your reputation or worse. Choosing a TIER 3 datacenter ensures your IT systems are always available. 

The core task of a datacenter is to house the IT environments of their clients. It should therefore come as no surprise that all resources such as cooling, floor load, power supply, emergency power and UPS systems are aligned perfectly. Due to this calibration, colocation is much preferred to having a server room on premise. The availability offered by a professional datacenter is for many businesses simply impossible to achieve.

TIER-classification datacenters

There are differences in the percentage of availability a datacenter can guarantee. The Uptime Institute, an advisory organization that focuses on improving the performance, efficiency, and reliability of business critical infrastructures, defines four different datacenter ‘tiers’. These levels say something about the availability and maximum downtime of a datacenter.  A TIER 1 datacenter offers no redundancy. A TIER 3 datacenter offers partial redundancy. A TIER 3 datacenter offers N+1 and a TIER 4 2N+1. This means that in a TIER 3 datacenter all resources have been redundantly installed. With a TIER 4 datacenter they even guarantee a backup of the backup. This also means that the energy power supply has to be redundantly installed, something that within the Netherlands (with its single power network) is quite tricky to do.

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Which availability is required?

The highest availability of course also has a high price. That’s why the question is, what level of availability is required by your organization? For example, a hospital will will always choose the highest possible availability, because the unavailability of systems wouldn’t just cost money and reputation, but could even cost lives. In practice it has become apparent that for most organizations a TIER 3 datacenter will suffice.

Optimal redundancy is not essential to every organization. Whether it is for your organization depends on how much being down would cost your business. How many employees won’t be able to do their jobs? How many customers can’t be helped? How much revenue does the business lose? But also: what does downtime mean for the reputation of your business, and can you expect damage claims? This risk assessment determines whether the costs of damage with a possible disruption can counterbalance the cost of a higher availability. Often, a combination of on premise computer space for less critical processes and a TIER 3 colocation for business critical applications and data can achieve the right level of availability at acceptable prices.

Availability checklist

To make an informed decision, you can ask yourself the following questions:

  • What is the maximum amount of downtime permissible by your organization?
  • How is the availability of the datacenter guaranteed?
  • Are redundant resources physically separated?
  • Is availability guaranteed during maintenance activities?


100 percent uptime

The datacenters of The Datacenter Group in Amsterdam, Delft, Rotterdam and Utrecht have realized an uptime of 100 percent since the companies’ founding in 2007. With colocation clients can choose an SLA that offers 2N or an SLA that offers N+1. This provides them with two completely separate 2×32 ampere power feeds. These feeds have their own room dividers, separate UPS resources and separate generators. The installations and resources have been built according to the TIER 3 standard, in other words: with double the assurance, which reduces the chance of downtime to a minimum.

Layout of TIER-levels at The Datacenter Group

Tier 3 Tier 4 Uitleg SLA

SLA GuaranteeFeedsMaximum downtimeTechnical solution
Gold2N99.999%A feed

B feed

0,4 hours per yearThe A and B feed are fuelled by separate UPS systems, batteries, and emergency power systems. The capacity used is reserved in full on both installations.
SilverN+199.99%A feed

B feed

1,6 hours per yearThe A and B feed are fuelled by separate UPS systems and batteries, but connected to the same emergency power system. The capacity used is reserved in full on both installations.


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