Data Center Storage

Chapter 2

Power and AC

We are going to make some simplifying assumptions (approximations) to avoid setting ourselves up for failure by including too many variables and going for 100% accuracy. The problem of power becomes unmanageable if we try to understand all the dynamics—data grows over time, situations change depending on time of day or time of month. Rather we will sign up for simplifying assumptions, set up a solvable problem, and generate a useful, informative analysis.

About drive power, active, idle, and sleep, spec sheets for most hard drives show power in three ratings (see Table 2.1).

Table 2.1 The Tradeoffs Between Form Factor, Spin Speed, and Capacity

Source: HDD data sheets

Key Concepts

■  Active power is only slightly ...