miller60 writes "In their efforts at uptime, are data centers relying too much on infrastructure and not enough on best practices? That question is at the heart of an ongoing industry debate about the merits of the tier system, a four-level classification of data center reliability developed by The Uptime Institute. Critics assert that the historic focus on Uptime tiers prompts companies to default to Tier III or Tier IV designs that emphasize investment in redundant UPSes and generators. Uptime says that many industries continue to require mission-critical data centers with high levels of redundancy, which are needed to perform maintenance without taking a data center offline. Given the recent series of data center outages and the current focus on corporate cost control, the debate reflects the industry focus on how to get the most uptime for the data center dollar."