What are data centre tiers

Data centre tiers are a standardised system used to define specific types of data centre infrastructure. They indicate the reliability of that infrastructure. The tier rating relates to what a data centre can deliver in terms of reliability and performance, so failing to identify the right tier can lead to downtime issues or unnecessary expenses for any organisation. The classification ranks data centres from 1 to 4, with 1 being the worst performing level and 4 the best.

What determines the data centre tier standards?

The data centre tier system was designed by the Uptime Institute to classify data centres. The institute determines the criteria for each tier and list several values that together make up what constitutes the standards of data centre tiers. Key factors include:

Performance: Standards are performance-based. This means that any systems which meet the need for fault tolerance, redundancy, and fault availability is acceptable.

Technology neutral: Tiers don’t require specific technologies in order to be classified, primarily due to the fact that the latest advanced technologies consistently disrupt the digital transformation environment.

Vendor neutral: The brand of technology used in a data centre is not considered as a factor in determining the tier, meaning centres are judged purely on their capabilities.

What factors are considered for data centre tier classification

The Uptime Institute keeps the exact method of assigning tiers under tight wraps, but most key metrics are widely known and understood.

The Institute considers the following factors when rating a facility:

  • Carrier neutrality
  • Data centre security levels
  • Operational sustainability and the centre’s ability to deliver on long-term operational targets.
  • Redundancy levels (the process of duplicating critical components and maintaining them as fail-safes and backups in case of planned or unplanned disruptions).
  • Uptime guarantees and service availability
  • Service cost
  • Staff expertise and maintenance protocols (particularly the ability to handle concurrent maintainability)
  • The state of power infrastructure and cooling
  • The time a facility needs to set up a new client

The tiering system does not necessitate the use of any specific technologies or design choices. The freedom to choose between solutions grants flexibility when meeting tier goals, so every data centre can choose the best way to meet the standards and reach the desired rating.

Data centre tier rating

Tier 1 Data Centre – Tier 1 Data Center (Basic capacity)

A Tier 1 data centre is the lowest-rated tier and is considered the least reliable. This is because a data centre adhering to Tier 1 standards can only guarantee an uptime of 99.671% and lacks IT equipment that supports redundancy. It is likely too that the business will be out of action every time the data centre shuts for maintenance.

Tier 2 Data Centre

Tier 2 data centres offer all the capabilities of Tier 1 but also include redundant components for additional capacity. These components frequently include engine generators for backup power, pumps or chillers for additional and more reliable equipment cooling, and dedicated UPS modules for more reliable electricity, without the need to suffer from sags and power spikes.

This means that unlike a Tier 1, planned outages for maintenance won’t affect business uptime. However, a Tier 2 will offer a significantly lower uptime guarantee than a Tier 3 or 4 data centre.

Tier 3 Data Centre

These data centres are usually a good fit for most small and medium-sized businesses (SMBs). They should guarantee 99.98%+ uptime guarantee and often this is financially backed. With a Tier 3 data centre, there should be no downtime for maintenance – unless major work is needed. All equipment is dual-powered with multiple uplinks.

Tier 4 Data Centre

The Tier 4 data centre rating marks the highest standard for data centres – usually utilised by any business that requires constant availability. All equipment is fully fault-resistant. They have an uptime of 99.995%, which equates to annual downtime of no more than 26 minutes.

Data Center Tiers by Uptime

  • Tier I: 99.671% uptime; maximum downtime of 28.8 hours per year
  • Tier II: 99.741% uptime; maximum downtime of 22.7 hours per year
  • Tier III: 99.982% uptime; maximum downtime of 1.6 hours per year
  • Tier IV: 99.995% uptime; maximum downtime of 0.4 hours per year

How to choose the right data centre tier

As we have already seen, higher data centre tiers typically offer a more reliable service. However, selecting a tier 3 or tier 4 data centre does not always represent the right choice. Decision-makers should choose the data centre tier that most closely fits their business requirements. Certain types of organisations will typically veer towards choosing specific tiers.

The following is a brief breakdown of each tier’s typical customers.

Tier 1: These data centres are typically best suited to very small businesses looking for the most affordable hosting option. Small companies without complex IT requirements or the need to deliver service 24×7 can tolerate more frequent downtime

Tier 2: These facilities are a good option for SMBs that want a cost-effective option but one that nevertheless offers more reliability than tier 1. If an organisation’s online services aren’t business critical and it can accommodate some downtime, then a Tier 2 may meet its needs.

Tier 3: These types of data centres are favoured by SMBs whose IT operations need additional fail-safes over those basic protections offered by the lower tiers but who are still looking for a cost-effective option. Businesses that host extensive data sets (especially of customer data) are well-suited to this tier

Tier 4: This type of data centre is typically used by large, global businesses or public sector organisations that require uninterrupted availability. Organisations with mission-critical servers and intense customer or business demands would be well suited to a Tier 4 facility

Telehouse data centre services

Whatever the precise nature of the data centre services and connectivity that firms are looking for, Telehouse data centres offer a leading global standard. The company offers 24/7 remote hands and the ability to establish cross connects in a matter of days. It operates five data centres in London and has data centres based in multiple locations around the world, offering maximum data centre connectivity potential. With Telehouse, organisations have access to one of the world’s densest networks of carriers, ISPs, internet exchanges, cloud service and data centre providers. Telehouse also complies with the PCI Data Security Standard and also the Information Security Management System – ISO/IEC 27001:2013 as well as full CCTV surveillance, 360° monitored perimeter fencing and dedicated on-site security personnel 24/7.

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