qqp question1: How the specific uptime requirement in Data Center Tiers i.e. Tier1=99.671%, Tier2=99.741%, Tier3=99.982% & Tier4=99.995% were decided? question2: How can I build a 99.9999% uptime system? I have 40 servers, data base, deployment machine; mirrored to a second data center. How do I handle patches?