Tier 4

A Tier 4 data center is the most advanced type of data center tier, as classified by the Uptime Institute. These tiers are a standardized methodology used to determine availability in a facility. The Tier 4 data center is the most robust and less prone to failures. Its design ensures redundancy and reliability.

Tier 4 Data Center:

  1. Uptime: Designed for 99.995% availability.
  2. Redundancy: 2N+1 fully redundant infrastructure (the highest level of redundancy in a data center).
  3. Components: All components are fully fault-tolerant including uplinks, storage, chillers, HVAC systems, servers etc.
  4. Cooling: Fully redundant cooling equipment.
  5. Concurrent Maintainability: Everything can be maintained concurrently.
  6. Fault Tolerance: Fully fault-tolerant with the ability to sustain at least one worst-case scenario fault without impacting critical load.
  7. Power Paths: Multiple active power distribution paths.
  8. Downtime: Approximately 0.4 hours of downtime annually.
  9. Target Audience: Ideal for mission-critical operations such as large financial institutions, government data processing centers, and other high-demand networks.

Key Differences:

  • Redundancy: Tier 4 offers 2N+1 redundancy, meaning there is a double system for power and cooling (plus an additional backup), while Tier 3 typically offers N+1.
  • Fault Tolerance: Tier 4 is fully fault-tolerant, meaning that any single failure of components does not impact services, unlike Tier 3.
  • Power Paths: Tier 4 data centers have multiple active power paths, whereas Tier 3 has multiple paths but only one active at a time.
  • Downtime: Tier 4 data centers have significantly less downtime per year compared to Tier 3.
  • Cost and Complexity: Building and maintaining a Tier 4 data center is significantly more expensive and complex than a Tier 3 facility.

Choosing Between Them:

  • Cost vs. Need: Tier 4 data centers are significantly more expensive to build and operate. Organizations should assess whether they need the highest level of uptime and fault tolerance that Tier 4 provides.
  • Business Requirements: Businesses that can afford occasional downtimes for maintenance or those that don't have extremely critical data operations may find Tier 3 facilities adequately sufficient.
  • Industry Compliance: Certain industries may require or favor Tier 4 facilities due to regulatory requirements.

In summary, while both Tier 3 and Tier 4 data centers are designed to ensure high levels of uptime and reliability, Tier 4 takes this a step further with increased redundancy, fault tolerance, and a correspondingly higher price point.