![[Screenshot 2025-07-02 at 18.25.25.png]] ![[Pasted image 20250603000414.png]] - **Tier 1**: - Basic site infrastructure with a single path for power and cooling. - Provides 99.671% uptime. - No redundancy; planned and unplanned maintenance can cause downtime. - **Tier 2**: - Redundant capacity components for power and cooling. - Provides 99.741% uptime. - Partial redundancy (N+1); some components can be taken offline for maintenance without affecting operations. - **Tier 3**: - Multiple independent distribution paths serving IT equipment. - Provides 99.982% uptime. - Concurrently maintainable; any component can be removed or replaced without downtime (N+1 redundancy for power and cooling). - **Tier 4**: - Fault-tolerant site infrastructure with completely redundant systems. - Provides 99.995% uptime. - 2N+1 redundancy; ensures highest level of fault tolerance and reliability. Operations continue even if multiple components fail. ## ISO standards x Tiers - **Data center tiers** are about **infrastructure robustness, redundancy**, and **uptime**. A higher tier (III or IV) means the data center has more resilient infrastructure to ensure continuous operations. - **ISO standards** focus on **processes**, **management practices**, **security**, **efficiency**, and **environmental responsibility**. They provide frameworks that support best practices in security (ISO 27001), business continuity (ISO 22301), service management (ISO 20000-1), and sustainability (ISO 50001, ISO 14001). - Higher-tier data centers (Tier III and IV) often pursue ISO certifications to align their robust infrastructure with best practices in security, operations, and environmental management.