Measuring Capacity and Idle Resource Usage 113
For example, marketing may not factor in bandwidth versus I/O-inten-
sive applications or the cost and applicable data-protection level. Another
issue with “magic” metrics, like the one in the previous example, is that they
can be mistakenly used to try and measure different types, tiers, and categories
of storage. Another common mistake is to use raw disk drive numbers for the-
oretical performance, rather than combined storage controller and disk drive
performance based on industry standard or other acceptable benchmarks. For
true comparison purposes, look at applicable metrics relevant to the task and
reflective of the function for which the resource will be used.
5.4 Measuring Capacity and Idle Resour ...